How Does Poor Deliverability Drain Your Marketing ROI?

Kristen Wyatt on September 23, 2025

You know that feeling when you’ve poured your heart into an email campaign, the design is spot-on, the subject line is clever, and the offer is your best one yet. You hit send, lean back, and wait for the results to roll in. But to your surprise, the inbox remains quiet. The open rate is insanely low. What’s the issue?! The problem might not be your content at all. It might be something far more fundamental: poor email deliverability.
We spend so much time optimizing for opens and clicks that we forget a simple, but brutal truth: If your emails don’t make it to the inbox, nothing else matters! Every dollar you spent on acquiring that subscriber, every hour you invested in crafting that perfect message, all evaporates before anyone has a chance to see it.
Let’s talk about the real-world connection between deliverability and your marketing ROI. It’s the foundation of your “marketing house”. If it’s crumbling, everything built on top becomes unstable. Consider this in simple terms: imagine you have 10,000 subscribers. With excellent deliverability, maybe 9,800 of your emails land perfectly in primary inboxes. Your potential audience is 9,800 people.
Now, imagine your deliverability is struggling, and only 70% of your emails get through. Suddenly, your audience shrinks to 7,000 people. You’ve lost 2,800 potential customers without changing a single word. That’s a 28% hit to your potential revenue right off the top. You’re basically lighting a chunk of your marketing budget on fire before you even start.
The financial drain goes deeper than just a smaller audience, though. It creates a vicious cycle. First, you’re wasting your acquisition costs. You paid for those subscribers, whether through ads, content, or a valuable lead magnet. When an email bounces or gets filtered as spam, that investment is wasted. That subscriber becomes a cost with zero return.
Then, there’s the inflated cost per conversion. If a campaign costs $1,000 and generates 100 conversions with good deliverability, your cost per conversion is a healthy $10. But if poor deliverability means you only get 70 conversions for that same $1,000, your cost per conversion jumps to over $14. Your campaign suddenly looks inefficient when the real problem is that no one saw it.
Arguably, the most dangerous cost is the hidden one: reputation damage. Poor deliverability is usually a symptom of a poor sender reputation. ISPs like Gmail and Outlook are constantly watching. When they see low open rates and people hitting “report spam,” they get the message that your emails aren’t welcome. This starts a downward spiral where low engagement leads to even lower inbox placement. And this hurts engagement even further. Digging out of that hole can be a long and painful process.
So, how can you tell if this is happening to you? A sudden, sustained drop in open rates is a classic clue. Are your click-through rates mysteriously low? It might not be your call-to-action; it might be that people aren’t seeing the email. Keep an eye on your bounce rates and spam complaints, as even a small number can raise big red flags.
The good news is that you can fix this. It’s about going back to basics and building trust. Start with permission. Only email people who genuinely asked to hear from you. Purchased lists might seem tempting, but they are more than likely going to be a shortcut to the spam folder that can poison your reputation.
Keep your list clean. It’s tough, but you need to let go of subscribers who haven’t engaged with your emails in months. They’re not just inactive, they’re actively telling ISPs (by not opening) that your content isn’t interesting. A smaller, engaged list is far more valuable than a large, unresponsive one.
On the technical side, make sure your emails are authenticated. This sounds complicated, but it’s just about proving you are who you say you are. Tools like SPF, DKIM, and DMARC tell inbox providers you’re a legitimate sender, not a scammer.
And perhaps the simplest tip of all: make it easy to leave. A clear, one-click unsubscribe link might feel like you’re encouraging people to go, but it’s much better than the alternative. When people can’t easily unsubscribe, they get frustrated and hit “report spam,” which can be a major blow to your reputation.
It really all comes down to sending emails that people want to get. When you focus on relevance and value, your audience engages. They open, they click, and they reply. And that positive engagement is the single most powerful signal to ISPs that you’re a sender worth delivering.
Stop thinking of deliverability as an IT issue. It’s a revenue issue! By taking regular care of your sender reputation, you’re not improving a number on a dashboard and making sure your creativity, strategy, and budget are actually reaching human beings. You’re protecting the very return on your investment. Remember that an email that never arrives at its destination has an ROI of zero.

Finding Balance with AI

Kristen Wyatt on August 26, 2025

Let’s be honest, if you’re in marketing, you’re feeling the pressure to adopt AI. The buzz is everywhere and the promise is incredible: hyper-personalized content, campaigns launched at a massive scale, and data-driven decisions that promise to finally unlock a boost in engagement.

But here’s the uncomfortable catch that often gets lost in the hype, the same AI tools designed to lift your engagement can actually become the thing that sabotages your sender reputation! Implementing AI in your email strategy isn’t a simple “set it and forget it” task. It’s a lot like a tightrope walk, a constant and conscious balance between huge reward and significant risk.

Why is the risk so high? The line between genius and generic is actually incredibly thin. The same sophisticated language model that crafts a seemingly high-converting subject line can also populate your email body with phrases that trigger spam filters. It can personalize a message with so much specificity (example: “Hope you’re enjoying that blue sweater you left in your cart 43 days ago!”) that it creeps a subscriber out, prompting them to hit the ‘report spam’ button. The efficiency that allows you to create ten emails in the time it used to take to make one also paves the way to potentially alienate your audience ten times faster. And at this point, a single misstep can have a cascading effect. The ultimate risk is a potentially damaged sender reputation, which we all know is a really fragile asset to lose (and takes a lot of hard work to rebuild).

So, how do marketers navigate this without falling off the wire? The first and most important step is a mental shift. We have to reframe how we see these powerful tools. Think of AI as your new, overly eager intern who can be brilliant, fast, and never sleeps. It can generate a dozen draft variations in seconds, crunch massive datasets to identify hidden patterns, and segment lists with a precision that would take a human days. But would you let a new intern have the final sign-off on a major client campaign without oversight? Of course not! They lack context and strategic judgment. The final decision-making and calculated oversight must come from you. A human should always be in the loop, applying the brand voice, checking for appropriate tone, and confirming that the message feels authentically human (rather than off-puttingly robotic).

This “human-in-the-loop” model means your role evolves into that of an auditor before every send. This involves a few big checkpoints:

  • Spam Check: Never skip running AI-generated subject lines and copy through a dedicated spam filter checker. What sounds good to AI might read like a spam trigger to a filter.
  • The Read-Aloud Test: This is a simple, but powerful trick. Read the email out loud. Ask yourself – Does it flow naturally? Does it sound like something a real person would say in a conversation? Does it have that overly salesy “AI feel” to it?
  • Fact-Check Everything: AI models can occasionally pull incorrect information. This can lead to potentially disastrous personalization, like referencing an offer that doesn’t exist or a product feature that’s inaccurate. Verifying every dynamic element, link, and personalized claim is non-negotiable for maintaining customer trust.

Your auditing role also extends to list management. Use AI as a guide for list hygiene, not an automatic executioner. Allow it to identify disengaged segments or potentially risky addresses. But once that step has been done, you need to apply your human-led policies. Before suppressing 10,000 contacts, use that insight to launch a thoughtful, human-designed re-engagement campaign. This can preserve your list integrity and protect your reputation.

Finally, the golden rule: start small. Don’t attempt a full-scale AI revolution across all of your campaigns on day one. Choose a single segment or campaign type and run controlled A/B tests. Pit your best human-written email against the AI-assisted version. But keep in mind,  your monitoring should go beyond opens and clicks. Keep a close eye on spam complaints, unsubscribes, bounce details, and reply rates. These are your early warning signals for reputation damage.

The primary driver to your success utilizing AI is to stop thinking it as a self-governing employee and start treating it as that energetic intern. It is a force that can do the heavy lifting and generate incredible ideas. But it must be managed, guided, and repeatedly checked by a human expert. Use AI to sharpen your tools and enhance your creativity, not to replace your strategic brain. Find that balance!

The Dangers of List Fatigue (And How to Refresh It)

Kristen Wyatt on July 21, 2025

Email marketing is a powerful tool until your subscribers stop engaging. List fatigue occurs when your audience becomes unresponsive due to over-messaging, irrelevant content, or simply losing interest over time. Ignoring this problem can lead to serious consequences including lower engagement rates, damaged reputation, and having your email flagged as spam. The good news is that with the right strategies, you can revive your list and reconnect with inactive subscribers.

When subscribers disengage, it means more than fewer opens and clicks. It can harm your entire email program! Low engagement signals to internet service providers (ISPs) that your emails may not be valuable. This increases the chances of being sent to spam folders. Over time, this can hurt your deliverability and will make it harder for even your most engaged subscribers to see your messages. And remember, sending emails to inactive users wastes resources without providing any return on investment.

Here are some easy to follow steps that will help you refresh your email lists:

1. Clean Up Your List

Maintaining a clean email list is incredibly important for optimal performance. Start by identifying and removing inactive subscribers: those who haven’t opened an email in six months or more. It might feel counterproductive to shrink your list. But keeping disengaged contacts only drags down your metrics. Next, verify email addresses using tools like Inbox Monster’s Subscriber Insight to eliminate invalid or outdated entries. Finally, immediately remove any hard bounces (emails that no longer exist) to protect your overall sending reputation.

2. Run a Re-Engagement Campaign

Before removing inactive subscribers entirely, try to win them back with a targeted re-engagement campaign. A simple “We Miss You” email with a special offer (like a discount, complimentary resource, or exclusive content) can reignite their interest. Alternatively, ask for feedback with a short survey or a direct question like, “Do you still want to hear from us?”. For those who remain unresponsive, a final notice can prompt action and give them one last chance to stay.

3. Segment Your List for Better Targeting

Not all subscribers interact with your emails the same way. Segmentation is key to keeping them engaged. Divide your list based on engagement levels, sending different content to active users versus those who are slipping away. You can also segment by interests, using past behavior like clicked links or past purchases to personalize messaging. Demographic data (such as location age, or job role) can further refine your targeting, making sure subscribers receive content that truly resonates with them.

To avoid list fatigue in the long run, focus on sending fewer, but higher-quality emails. Test different send times and frequencies to find what works best for your audience. Most importantly, keep a close eye on key metrics like open rates, unsubscribe rates, and spam complaints. These will help you spot fatigue early and adjust your strategy before it becomes a bigger problem. List fatigue is a common challenge in marketing, but it doesn’t have to be permanent! By regularly cleaning your list, running strategic re-engagement campaigns, and leveraging segmentation, you can keep your audience active and interested. The result? Better deliverability, stronger engagement, and a healthier return on your marketing efforts.

Spam-Proof Your Campaign with the 80/20 Rule

Kristen Wyatt on June 23, 2025

When it comes to email marketing, there’s a fine line between an eye-catching design and a message that gets flagged as spam. One of the biggest mistakes marketers make is not paying enough attention to the balance between images and text. Too many visuals, and spam filters might place your mail into Spam. Too much plain text, and your email risks looking boring and getting ignored. So, what’s the ideal image-to-HTML ratio, and why does it matter for your email campaigns?

Spam filters are always on the lookout for suspicious activity. Since several phishing scams use image-heavy emails to avoid detection, major providers like Gmail and Outlook tend to distrust messages that don’t have enough text. If your email looks like a giant image with little to no readable content, it’s more likely to end up in the junk folder. On the other hand, if your email is nothing but a wall of text, subscribers might lose interest before they even reach your call-to-action.

Experts suggest sticking to roughly 80% text and 20% images. This ratio keeps spam filters happy while still allowing for engaging visuals. This tends to work because spam algorithms prefer emails with enough readable content to analyze. But that doesn’t mean you should avoid images altogether. They can make your emails more appealing, reinforce your brand, and help guide readers toward your main message. The trick is to use them strategically, rather than letting them dominate the campaign.

Another thing to keep in mind is how different clients handle images. Gmail, for example, will clip emails that exceed 102KB in size, forcing readers to click “View entire message” to see the full content. Outlook (by default) blocks external images unless the user manually enables them. This means your email could look broken if you’re relying too much on visuals. On mobile devices, oversized images might get scaled down awkwardly, messing up the layout. To avoid these issues, always compress your images, add descriptive alt text, and test how your email looks with images disabled.

So, how do you put this into practice? First, never hide critical information inside an image. If the image doesn’t load, that message disappears. Instead, make sure anything important is also written in plain text. Second, optimize your images so they load quickly without sacrificing quality. And finally, always preview your email with images turned off to make sure it still makes sense.

Different industries may need slight adjustments to this rule. A fashion brand might get away with more images since visuals are a big part of their appeal. But a B2B software company might see better results with a more text-focused approach. The best way to find your sweet spot is through testing! Track your open rates, click-through rates, bounce details, and spam complaints to see what works best for your audience.

The ideal image-to-HTML ratio ultimately depends on your specific audience and industry. While the 80/20 rule serves as a reliable starting point, continuous testing and optimization will reveal what resonates best with your subscribers. By maintaining this balance, marketers can achieve both strong inbox placement and meaningful engagement with their email campaigns.

A Quick Guide to SNDS

Kristen Wyatt on May 27, 2025

Deliverability is arguably a cornerstone factor for most businesses that rely on email marketing, transactional messages, or any form of email communication. Microsoft (which powers Outlook, Hotmail, Live, and MSN) employs strict spam filters to protect its users. To help legitimate senders monitor their performance, Microsoft offers the Smart Network Data Services (SNDS) platform.

In this blog, we’ll explore what SNDS is, the key metrics it can provide, and best practices to maintain a strong sending reputation with Microsoft’s services. By following these guidelines, you can improve inbox placement and avoid being flagged, throttled, or even blocked.

SNDS is a free analytics tool designed to help email senders monitor their performance across Microsoft’s network. It provides guidance for how Microsoft’s spam filters are handling your mail, allowing you to identify and resolve potential issues before they hurt your overall deliverability.

To start using SNDS, you first need to sign up at https://snds.microsoft.com. After registering, you should add your sending IP addresses to track their reputation. Microsoft may require verification to confirm IP ownership. Be prepared to provide necessary documentation. Once your request is approved, you’ll gain access to detailed reports that provide valuable insights into your email deliverability status. This will help you monitor and improve your sender reputation over time.

SNDS provides several important metrics that influence your reputation. Understanding these can help you optimize your email strategy.

1. IP & Domain Reputation

Microsoft categorizes your sending reputation into three distinct levels. A green status indicates good standing. This means your emails usually land directly in recipients’ inboxes. When your reputation shifts to yellow, it signals potential issues and some of your emails. You may start being diverted to spam folders. The most serious red status points to poor reputation with a high likelihood of being marked as spam. Your emails may be blocked entirely with this status. If your reputation drops to yellow or red status, it’s important to investigate and address the underlying issues immediately to restore your deliverability.

2. Spam Complaint Rate (SCR)

Microsoft monitors your Spam Complaint Rate (SCR) closely. The SCR measures how frequently recipients mark your email as spam. This metric serves as an indicator of sending reputation, where a high complaint rate raises significant red flags with Microsoft’s filtering systems. Best practices recommend maintaining an SCR below 0.1%. This means no more than 1 complaint per 1,000 emails sent. To achieve this, senders should implement clear and easy ways to unsubscribe while making sure subject lines accurately reflect the content. These measures help maintain trust with both recipients and Microsoft’s email platforms, ultimately supporting better deliverability.

3. Filtered Percentage

This metric shows how many of your emails are being sent to the Junk folder instead of the inbox. A sudden increase suggests deliverability problems.

4. Trap Hits

Microsoft uses spam traps to identify poor list hygiene. Hitting these traps severely damages your reputation. Inbox Rev recommends that you regularly clean your sending lists and remove inactive subscribers.

5. Volume & Traffic Trends

Monitoring your email volume and traffic trends is needed for maintaining good deliverability with Microsoft’s services. Sudden, unexpected spikes in sending volume can raise red flags with spam filters. This can potentially cause your mail to be blocked or diverted to junk folders. It’s important to maintain steady, consistent sending volumes. When you need to scale up your campaigns, the best approach is to implement gradual increases over time. This allows Microsoft’s systems to recognize your sending patterns as legitimate. This measured approach helps establish your reputation as a responsible sender and protects your deliverability rates.

To ensure your emails reach the inbox, follow these proven strategies.

1. Implement Proper Email Authentication

Microsoft prioritizes authenticated emails. Ensure you have:

  • SPF (Sender Policy Framework) – Verifies authorized sending IPs.
  • DKIM (DomainKeys Identified Mail) – Adds a digital signature to prove email integrity.
  • DMARC (Domain-based Message Authentication, Reporting & Conformance) – Tells Microsoft what to do if authentication fails (quarantine or reject).
  • Recommendation: A strict DMARC p=reject policy improves trust with Microsoft.

2. Maintain a Clean Email List

Sending to invalid or inactive addresses hurts your reputation.

  • Use double opt-in to confirm subscriber consent.
  • Remove hard bounces immediately.
  • Regularly prune inactive subscribers (no opens/clicks in 6+ months).

3. Minimize Spam Complaints

High complaint rates lead to filtering.

  • Provide a clear, one-click unsubscribe option.
  • Avoid deceptive subject lines.
  • Segment your lists to send more relevant content.

4. Warm Up New IPs Gradually

New IPs with sudden high volume look suspicious.

  • Start with low volumes.
  • Increase sending gradually (averaging around 4-6 weeks).

5. Monitor SNDS & Test Email Placement

  • Check SNDS daily for reputation changes.
  • Send test emails to Outlook accounts and check if they land in Inbox or Junk.

6. Avoid Spammy Content & Improve Engagement

Low engagement (poor open/click rates) signals spam risk.

  • Personalize emails when possible.
  • Avoid excessive promotional language.

7. Handle Bounces Properly

  • Hard bounces (permanent failures) should be removed.
  • Soft bounces (temporary issues) should be retried, but paused if persistent.

If your SNDS dashboard shows a decline, take these steps:

  1. Pause sending from affected IPs.
  2. Audit your email list for spam traps or inactive users.
  3. Check authentication (SPF, DKIM, DMARC) for errors.
  4. Request a review via Microsoft’s Junk Mail Reporting Program.

SNDS is an extremely important tool for any business sending email to Outlook, Hotmail, or MSN users. You can proactively maintain a strong sender reputation. Following best practices, such as proper authentication, list hygiene, and gradual IP warming, will help you avoid spam filters and maximize inbox placement. By staying vigilant and optimizing your email practices, you can create the best opportunity for reliable deliverability across Microsoft’s systems.

B2B vs. B2C: Understanding Key Differences

Kristen Wyatt on April 22, 2025

The best marketing efforts hinge on deliverability, which is the ability of an email to reach a recipient’s inbox successfully rather than being blocked or marked as spam. While the fundamental principles of email marketing apply across the board, the approach to deliverability varies between business-to-business (B2B) and business-to-consumer (B2C) campaigns. Understanding these differences is important for marketers aiming to optimize engagement, maintain sender reputation, and achieve measurable results.

B2B communications typically target professionals who engage with email in a structured and intentional way. Since these recipients evaluate purchases that could involve long sales cycles, their engagement tends to be more measured. Open rates in B2B environments are often higher because work-related emails are prioritized. But responses may take time! Research indicates that mid-morning or early afternoon on weekdays are optimal sending times.

On the other hand, B2C emails cater to individual consumers whose purchasing decisions are more likely to be impulsive and/or emotionally driven. The competition for attention is intense as consumers are constantly overwhelmed with promotional content. Successful B2C emails leverage urgency, personalization, and compelling visuals to prompt immediate action. Unlike B2B, where weekdays dominate, B2C campaigns are more likely to see higher engagement during evenings, weekends, or holidays.

The tone and content of B2B/B2C emails must support their respective audiences. When you are emailing business professionals, imagine you are preparing an executive briefing. These readers are assessing whether you understand their challenges as they assess your message. That is why the most successful B2B emails read like well-prepared insights rather than advertisements. We have seen clients transform mediocre campaigns just by shifting from generic product benefits to specific results.

On the consumer side, you are fighting for attention against baby photos, dinner plans, and viral memes, along with competitors. For B2C, the emails that cut through the noise feel like they are coming from a knowledgeable friend, rather than a faceless corporation.

Maintaining a clean email list is relevant for B2B and B2C campaigns, but the challenges differ. In B2B marketing, spam filters are notoriously strict. A single spam complaint or high bounce rate can severely damage sender credibility, especially since most B2B emails are analyzed through enterprise-level security systems. To reduce these risks, marketers should implement double opt-in processes, segment lists by industry or job function, and gradually warm up new domains to avoid triggering spam filters.

B2C lists face issues related to scale and unpredictability. Consumers frequently update email addresses, abandon old accounts, or use disposable emails for sign-ups. High bounce rates and inactive subscribers can harm deliverability. This makes having a real-time email validation tool beneficial. B2C marketers should also monitor spam complaints vigilantly since ISPs like Gmail and Yahoo aggressively filter promotional content.

Campaign successes are measured differently in B2B and B2C environments. B2B typically has higher open rates due to its professional relevance. But click-through rates (CTRs) may be lower due to recipients often requiring multiple touchpoints before converting. Spam complaints are especially damaging in B2B due to corporate filters imposing harsh penalties on senders with poor reputations.

B2C campaigns often see fluctuating open rates, but higher CTRs when promotions resonate with audiences. But the large volume of marketing emails consumers receive means that even minor missteps, like misleading subject lines or excessive frequency, can lead to increased unsubscribe rates and spam flags.

At the end of the day, email marketing succeeds or fails based on one simple question: Does this feel like a message the recipient actually wants to receive? B2B marketers must focus on building trust through professional, value-driven messaging while maintaining list hygiene. B2C marketers should prioritize engagement, mobile optimization, and rapid adaptability to shifting consumer trends. By customizing strategies to the unique demands of B2B and B2C email marketing, businesses can maximize deliverability, enhance engagement, and achieve sustainable growth.

The Key to Stopping Email Bounces

Kristen Wyatt on March 21, 2025

It’s no secret that email marketing is one of the most powerful tools to connect with your audience, build brand loyalty, and drive sales. But let’s be honest – nothing stings more than spending hours crafting the perfect email, hitting “send,” and later discovering it never reached your subscriber. This is where email bounces come into the picture. Bounces are a major factor in email deliverability. Understanding them can mean the difference between a successful campaign and one that falls flat. In this blog, we’ll explore what email bounces are, why they happen, and how you can effectively manage them to maintain a healthy sending list and improve your deliverability rates.

So – Why do bounces occur? An email bounce (or “bounce”) takes place when your email fails to reach the intended recipient’s inbox. Instead of landing in the inbox, it “bounces” back to you. Think of it as the digital version of a “return to sender” notice on a physical letter. Understanding where bounces come from is key to diagnosing and fixing deliverability issues. Bounces can stem from a variety of sources, ranging from technical problems to user behavior.

Let’s break them down into more detail:

1. Invalid or Nonexistent Email Addresses

One of the most common sources of hard bounces is sending email to addresses that don’t exist. This can happen for several reasons:

  • Typos during sign-up: A subscriber might accidentally type something like “gmaul.com” instead of “gmail.com.”
  • Deactivated accounts: The recipient might have deleted or abandoned their email account.
  • Disposable email addresses: Some users sign up with temporary addresses to access gated content, but these often expire quickly.

Consider using a double opt-in process during sign-up to tackle invalid or mistyped email addresses. This requires users to confirm their email by clicking a verification link. You can also use an email verification tool to catch typos or invalid formats before they’re added to your list. These steps will help keep your list clean and improve deliverability.

2. Domain-Related Issues

The domain (the part of the email address after the “@” symbol) can also cause bounces. Common domain-related problems include:

  • Nonexistent domains: The domain might not exist (example: user@nonexistentdomain.com).
  • Misconfigured DNS settings: The domain’s DNS records might not be set up correctly to receive email.
  • Expired domains: The domain may have expired or been deactivated.

Start by verifying domains during sign-up using an email validation tool. This ensures only legitimate, active domains make it onto your list. Regularly audit your list to remove domains that no longer exist. These steps will help keep your list healthy and reduce bounce rates.

3. Full Mailboxes

A soft bounce often happens when the recipient’s mailbox is full and can’t accept new mail. This is common with free email services like Yahoo or AOL which have storage limits.

In cases where an email cannot be delivered due to a recipient’s inbox being full, there’s little you can do immediately except wait and attempt to resend the email at a later time. If the issue persists, it’s best to remove the address from your list to keep it clean and avoid wasting resources. This approach helps to make sure your email list remains focused on active and reachable recipients.

4. Server Issues

Technical problems on the recipient’s side can also cause bounces. These include:

  • Server downtime: The recipient’s email server might be temporarily offline or undergoing maintenance.
  • Overloaded servers: High traffic or resource limitations can prevent the server from accepting new email.
  • Greylisting: Some servers temporarily reject mail from unknown senders as a spam prevention measure, but they usually accept the email on a later attempt.

For temporary issues, try resending the email after a few hours or days. Most email platforms automatically retry delivery over a set period. If the problem continues, remove the address from your list to maintain list hygiene.

5. Email Size and Content Issues

The size and content of your email can also trigger bounces. Some of the most common reasons include:

  • Large attachments: Campaigns with large attachments (over 10MB) may exceed the recipient’s server limits.
  • Spammy content: Certain keywords, excessive use of images, or poorly formatted HTML can trigger spam filters, causing the email to bounce.
  • Authentication failures: If your email lacks proper authentication (SPF, DKIM, DMARC), it may be rejected by the recipient’s server.

Start by compressing large attachments or replacing them with cloud storage links to reduce the likelihood of your email being flagged or blocked. Steer clear of spam-triggering words and phrases like “free,” “act now,” or “limited time offer,” as these can increase the chances of your content being marked as spam. Finally, confirm that your mail is properly authenticated (using protocols like SPF, DKIM, and DMARC) to verify your domain and enhance trust with email providers. These steps will help your email reach recipients’ inboxes more effectively.

6. Blocked Email

Sometimes, your mail is blocked by the recipient’s server or email provider. This can happen for several reasons:

  • IP/Domain blacklisting: If your sending IP address or domain is on a blacklist, your mail may be blocked.
  • Strict spam filters: Some organizations or email providers have aggressive spam filters that block email from unknown senders.
  • Recipient settings: The recipient may have manually blocked your email address or domain.

To resolve these issues, begin by checking if your IP or domain is listed on a blacklist using tools like MX Toolbox. If you are listed, follow the necessary delisting steps to request more information and address the underlying cause. If you’re sending email from a new domain or server, make sure to warm up your IP address gradually by increasing email volume over time to build a positive sender reputation. And encourage your subscribers to add your address to their contacts or whitelist. This can help confirm your mail consistently lands in their inboxes rather than spam folders. These proactive measures will improve your email deliverability and sender credibility.

7. Inactive or Abandoned Accounts

Over time, people stop using certain email accounts. But they may remain on your list. These accounts can lead to bounces if the provider deactivates them.

It’s important to regularly clean your lists by removing inactive subscribers who no longer engage with your email. Before taking this step, consider sending re-engagement campaigns to inactive users to give them an opportunity to reconnect with your content. If they still don’t respond, it’s best to remove them from your list. This practice improves your email engagement rates and helps to make sure your list remains focused on active and interested recipients that can positively impact your sender reputation and deliverability.

8. Role-Based Email Addresses

Role-based email addresses (for example: “info@company.com,” “support@company.com”) are often monitored by multiple people or automated systems. These addresses are more likely to bounce because:

  • They may not accept email from external senders.
  • They might have stricter spam filters.
  • They could be set up to automatically delete or reject certain types of mail.

Avoid sending marketing campaigns to role-based addresses, such as info@ or support@, unless you’re confident they are relevant and appropriate for your campaign. These addresses are often monitored by multiple people or automated systems. This makes them less likely to engage with your content. Instead, focus on targeting personal email addresses. These contacts tend to yield better engagement rates and provide more meaningful connections with your audience.

9. Seasonal or Temporary Issues

Sometimes, bounces are caused by temporary factors, such as:

  • Holiday auto-replies: Some email servers are configured to reject mail when the recipient is on vacation or has set up an auto-reply.
  • Temporary server rules: During high-traffic periods (for example, BFCM), some servers may temporarily tighten their spam filters.

If an email fails to deliver due to these issues (like having a recipient’s server being overloaded), try resending after a few days once the problem has had a chance to resolve itself.  It’s also important to monitor your bounce rates, especially during peak seasons when email servers often experience higher volumes. If you notice an increase in these bounces, consider adjusting your sending frequency or timing to reduce the strain on servers and improve deliverability.

To minimize bounces and enhance your marketing success, it’s incredibly important to take proactive steps that address the root causes. Start by using a reliable Email Service Provider (ESP) to automatically manage bounce-related issues, like retrying soft bounces and removing hard bounce addresses. Regularly monitor your sender reputation with tools like Google Postmaster or SNDS to catch and resolve potential issues early. Educate your subscribers to update their email addresses if they switch providers, helping your list to stay current. And don’t forget to test your campaigns before sending to check for size, formatting, and spam triggers. By understanding the causes of bounce issues and addressing them proactively, you can improve your email deliverability, reduce bounce rates, and position yourself so that your messages reach the right audience. Remember, a clean and well-maintained email list is the foundation of successful email marketing. So don’t skip the maintenance!

How to Prevent a Spam Trap Infestation

Kristen Wyatt on February 24, 2025

Spam traps can quietly ruin your email marketing efforts without you even realizing it. They sit unnoticed in your email list, waiting to damage your sender reputation, lower your deliverability rates, and hurt your overall campaign performance. But here’s the good news—spam traps are completely avoidable if you know what to look for. In this post, we’ll explain what spam traps are, why they matter, and how to steer clear of them. Plus, we’ll highlight one sneaky troublemaker that often gets overlooked: typo spam traps.

Spam traps are email addresses created by ISPs (like Gmail or Yahoo) or anti-spam organizations to catch senders who aren’t following best practices. First, there are pristine spam traps, which are email addresses that have never been used by a real person. These are designed to catch spammers who scrape or buy email lists. If you hit one of these, it’s a clear sign that your list-building practices need work. Then there are recycled spam traps, which are old, abandoned email addresses that ISPs repurpose as traps. If you’re emailing one of these, it means you’re not keeping your list clean and up-to-date.

But there’s a third type that often flies under the radar: typo spam traps. These are email addresses with intentional typos, like “gmial.com” or “yahooo.com.” They’re designed to catch senders who don’t validate their lists. Typo spam traps are especially sneaky because they can slip into your list through simple human error, like a subscriber mistyping their email address during sign-up. If you’re not using an email validation tool to catch these errors, you could be setting yourself up for trouble.

Spam traps might seem like a minor issue, but they can have major consequences for your email marketing. For starters, hitting a spam trap can damage your sender reputation. ISPs use spam traps to gauge your trustworthiness. So if you’re sending emails to them, it’s a red flag that you’re not following best practices. A damaged reputation makes it harder for your emails to reach inboxes. This means your campaigns are more likely to end up in spam folders or not get delivered at all.

Repeatedly hitting spam traps can get you blacklisted. This is email marketing purgatory, where your emails are blocked entirely by ISPs. Once you’re on a blacklist, it can be a long and frustrating process to get removed. In short, spam traps are not something you want to mess with.

The key to avoiding spam traps is good list hygiene and smart email practices. Here’s a few tips on how to keep your list clean and your campaigns effective:

First and foremost, don’t buy or rent email lists. This is Email Marketing 101. Purchased lists are a minefield of spam traps, fake addresses, and unengaged subscribers. Not only do they increase your risk of hitting traps, but they also hurt your engagement rates because the people on those lists didn’t opt in to hear from you. Building your list organically is the only way to go.

Next, use double opt-in. A double opt-in process makes sure that the people on your list actually want to be there. After someone subscribes, they receive a confirmation email asking them to verify their address. This simple step weeds out fake or mistyped addresses before they become a problem.

Clean your list regularly. Email lists decay over time. People change jobs, abandon old accounts, or simply lose interest. If you’re not cleaning your list regularly, you’re risking spam traps and wasting resources on unengaged subscribers. Use an email verification tool to scrub your list for invalid, inactive, or risky addresses.

Don’t forget about typo spam traps. These are email addresses with intentional errors, like “gmial.com” or “hotmal.com.” They’re designed to catch senders who don’t validate their lists. To avoid these, use an email validation tool that checks for typos and syntax errors. It’s a simple step that can save you a lot of headaches down the line.

Monitor your engagement metrics. Keep an eye on your open rates, click-through rates, and bounce rates. A sudden drop in engagement or a spike in bounces could be a sign that spam traps are lurking in your list. Remove inactive subscribers who haven’t engaged with your emails in 6-12 months (this is a best practices guideline metric. Create your own metrics that make the most sense for your company).

Segment your list. Not all subscribers are created equal. Segment your list based on engagement levels and tailor your campaigns accordingly. For example, send re-engagement campaigns to inactive subscribers before removing them entirely. This helps you maintain a healthy list while giving people a chance to re-engage.

Finally, stay compliant. Make sure you’re following email marketing laws like the CAN-SPAM Act (in the U.S.) and GDPR (in the EU). This includes having a clear unsubscribe link in every email and honoring opt-out requests promptly. Compliance isn’t just good practice—it’s the law.

If you’ve already hit a spam trap, don’t panic. Here’s how to recover. First, identify the source. Figure out where the spam trap came from. Was it a purchased list? An old, unengaged subscriber? A typo? Pinpointing the source will help you prevent future issues. Next, clean your list. Run your list through an email verification tool and remove any invalid or risky addresses. Then, reevaluate your practices. Take a hard look at your email marketing strategy. Are you following best practices? Are you regularly cleaning your list? Make adjustments as needed. Finally, if you’ve been blacklisted, reach out to your ISP. Contact the ISP or blacklist operator to explain the situation and request removal. Be honest and show that you’ve taken steps to fix the problem.

Spam traps might be sneaky, but they’re not invincible. By keeping your email list clean, following best practices, and staying on top of engagement, you can protect your sender reputation and you can make sure your emails land where they belong: in your subscribers’ inboxes! And don’t forget about typo spam traps! These little gremlins can slip through the cracks if you’re not careful, so make sure you’re using an email validation tool to catch them before they cause trouble.

At the end of the day, email marketing is all about building relationships. And just like any relationship, it requires care, attention (and a little bit of housekeeping). So roll up your sleeves, clean up that sending lists, and keep those spam traps at bay. Your inbox (and your subscribers) will thank you.

What Is Email Deliverability and Why Does It Matter?

Kristen Wyatt on January 27, 2025

Whether we’re talking to friends or running a business, email is a huge part of how we communicate. For companies, the value of email lies in its ability to reach customers. But this only works if the emails make it to their inboxes. Email deliverability is about making sure your emails don’t get blocked or sent to the spam folder. If your goal is to connect with people, understanding how deliverability works is key.

Here’s why this matters: When you send an email, you want the person to actually see it. If it ends up blocked or stuck in a spam folder, your message doesn’t get through. Good deliverability means your emails are more likely to land where they’re supposed to (which is in the intended recipient’s inbox) so more people can read them.

If your emails keep hitting spam folders, people (and email providers) might start seeing you as untrustworthy. This can result in a nasty reputation issue. But when you send emails that people actually want, you build trust and a good reputation. That makes it more likely your emails will get treated like the real deal.

Email marketing can be super effective, when it works. But if your emails don’t reach the people they’re meant for, they’re not doing much good. Making sure your emails get delivered means more people see them, engage with them, and take action.

And don’t forget, you have to play by the rules! For example, you have to make sure people actually agreed to get your emails. Ignoring rules like this hurts your deliverability. But it could get you into some real trouble, even legally. Sending emails the right way keeps you out of hot water and it helps your messages reach their audience.

Deliverability is influenced by a few main factors, starting with your reputation as a sender. Email providers keep tabs on how you’ve handled past emails – things like bounces, spam reports, and low engagement. If your track record isn’t great, it can hurt your chances of reaching your email’s intended destination. On the other hand, a solid history makes it more likely your emails will get through to the inbox.

Authorization is another big piece of the puzzle. Tools like SPF, DKIM, and DMARC help verify to email providers that you are a legitimate sender and that you’re not pretending to be someone else. Without proper authentication, your emails are more likely to get blocked or flagged.

The content in your email also matters. Misleading subject lines, too many links, overly large images, or anything that seems spammy can raise red flags. Keeping your emails simple, clear, and relevant makes them less likely to run into issues.

Your contact list plays a role too. Outdated or fake email addresses can drag down deliverability. Regularly cleaning up your active sending list and only emailing people who actually want to hear from you helps keep things on track.

Finally, how you send emails is very important. Blasting out too many too quickly or at irregular times can look suspicious. A steady, reasonable sending schedule indicates to email providers that you’re not a spammer.

How to Do It Better

  1. Watch Your Results: Keep an eye on how your emails perform. If something isn’t working, adjust your approach.
  2. Set Up Authentication: Use tools like SPF, DKIM, and DMARC so email providers know you’re a legitimate sender.
  3. Write Clearly: Avoid anything that might look suspicious to spam filters. Make your emails straightforward and relevant.
  4. Know Your Audience: Group your contacts based on what they’re interested in, so you can send emails they care about.
  5. Clean Up Your List: Remove inactive or fake email addresses to avoid bounces and complaints.
  6. Test and Adjust: Try different subject lines or formats to see what works best and keep improving.

Email deliverability comes down to making sure your messages actually reach the people you’re trying to connect with. By sticking to straightforward, honest practices and staying tuned into what works, you can ensure your campaigns hit the mark and make a real and positive impact.

The Importance of Mobile Optimization for Deliverability

Kristen Wyatt on June 12, 2024

It is 2024 and most people are checking their emails from their mobile devices. A mobile device is defined as a piece of portable electronic equipment that has internet connection capabilities.  It’s important to realize that those ‘mobile devices’ aren’t always just smartphones. People are consuming and sending email from tablets, smart watches, and even game consoles now! Due to this shift, it is more important than ever to optimize your email campaigns. In this blog, we’ll look at how mobile devices affect email deliverability and we will share some practical tips for making sure your emails engage mobile users.

Over 70% of email opens are estimated to occur from mobile devices. This trend underscores the need to make sure emails are mobile-friendly. A good mobile design not only enhances the user experience, but also boosts metrics like open rates and click-through rates. When email is optimized for mobile, users are more likely to engage with the content, leading to higher conversion rates and a stronger return on investment (ROI) for your email marketing efforts.

Even though mobile email usage is widespread, optimizing email for mobile is not always the easiest task. Design elements that look great from a desktop might not work on smaller screens. Plus, slow loading times and formatting issues can hurt email deliverability on mobile devices. These problems can frustrate users, causing them to delete your emails or unsubscribe from your mailing list altogether. Therefore, it is very important to address these issues on a proactive basis.

To tackle these challenges and to improve email deliverability for mobile users, try these tips:

  • Use a responsive design: Create emails that adjust smoothly to different screen sizes and orientations. A responsive design helps to make sure your email looks great whether it’s viewed on a smartphone, tablet, or laptop. This adaptability enhances the overall user experience and makes your email more accessible to a broader audience.
  • Simplify content: Keep your content short and easy to scan, perfect for shorter attention spans on mobile devices. Use concise headlines, bullet points, and clear paragraphs to convey your message quickly and effectively. This approach caters to mobile users and improves readability for everyone.
  • Provide a clear call-to-action (CTA): Make sure CTAs are easy to tap on mobile screens to drive user engagement. Use large, well-placed buttons that stand out and are easy to interact with. A clear CTA can significantly increase the chances of users taking the desired action, like making a purchase or signing up for a newsletter.
  • Test across devices: Test your campaigns on various mobile devices and email clients to ensure they perform consistently. This step is crucial for identifying and fixing any issues that might arise on different platforms. Regular testing helps maintain a high standard of quality and ensures that your emails deliver a seamless experience to all recipients.

Boost your email campaigns by taking advantage of mobile-specific features:

  • Utilize pre-header text: Use pre-header text effectively to add context and encourage recipients to open your mail. The preheader text, which appears alongside the subject line for many email clients, can be a powerful tool for enticing users to open your email. Make sure it complements your subject line and provides additional incentive for recipients to engage with your content.
  • Optimize for touch: Design buttons, images, and links to be touch-friendly to improve the user experience on touchscreens. Touch-friendly designs ensure that users can easily interact with your email, making it more likely that they will click through to your website or landing page.
  • Incorporate mobile-specific features: Include features like click-to-call or interactive elements to enhance user engagement. Click-to-call buttons allow users to call your business directly from the email, which can be especially useful for customer service or sales inquiries. Interactive elements, such as carousels or sliders, can make your emails more engaging and visually appealing.
  • Track mobile-specific metrics (like open rates and click-through rates) to evaluate your email campaigns’ success. Use analytics tools to understand user behavior and preferences. You can use this data to improve future mobile email campaigns. Email on Acid and Inbox Monster are two platforms that can be utilized in order to confirm your campaign optimizations. These tools offer insights into how your emails perform across different devices and can help you identify areas for improvement.

That said, it is obvious that mobile optimization is a must for email marketers. By understanding the impact of mobile devices on email deliverability and by following the tips in this blog post, you can ensure that your email campaigns resonate with mobile users. This ultimately leads to better engagement and deliverability.