Want fewer bounced emails? Here’s how to fix it.
Managing your email bounce rate is key to improving your email campaigns. A high bounce rate can hurt your sender reputation, lower deliverability, and even get your emails flagged as spam.
Bounced emails waste resources and damage your sender reputation. ISPs monitor bounce rates, and higher rates can lead to your emails being flagged as spam or blocked altogether.
Focus on email list hygiene, proper authentication, and regular monitoring to keep your campaigns effective and your bounce rate low.
Understanding why emails bounce is essential for protecting your sender reputation and improving deliverability. With 31 billion emails bouncing daily, knowing the root causes can make or break your email campaigns. Let’s dive into the main reasons behind both hard and soft bounces.
Hard bounces are permanent delivery failures that require immediate action. When an email cannot be delivered due to a lasting issue, it’s classified as a hard bounce.
"A hard bounce is a permanent failure of email delivery. It indicates that there will be no further attempt to deliver a message, and you must find a different way to reach the recipient." - Denys Velykozhon, Marketing Lead @Railsware
These failures often occur because of:
Email systems flag hard bounces using bounce codes that begin with 5.X.X. When this happens, most email platforms automatically remove the problematic address to prevent further damage to your sender reputation. However, the initial bounce can still hurt your standing with Internet Service Providers (ISPs).
To manage hard bounces effectively, remove invalid addresses as soon as they’re identified. You can also minimize these errors by double-checking for typos in your subscriber list and using email validation tools during signups.
Soft bounces indicate temporary delivery issues that might resolve on their own. Unlike hard bounces, these failures suggest that the email could succeed if retried later.
Some common reasons for soft bounces include:
Soft bounces are identified by bounce codes starting with 4.X.X. While these issues are often temporary, they can still harm your sender reputation if they persist. It’s worth noting that most email providers will convert repeated soft bounces into hard bounces after multiple failed attempts.
| Issue Type | Soft Bounce | Hard Bounce |
|---|---|---|
| Nature | Temporary delivery issue | Permanent delivery failure |
| Common Causes | Full mailbox, server down, large email size | Invalid address, non-existent domain, blocking |
| Resolution | Often self-resolves, may require content adjustment | Requires removing address from list |
Even though soft bounces seem less severe, they shouldn’t be ignored. Keeping your bounce rate below 10% is critical to maintaining a good sender reputation.
Neglecting email list maintenance can lead to a host of deliverability problems. Each year, about 22.5% of valid email addresses become outdated, as people change jobs, abandon accounts, or switch providers. Continuing to email these invalid addresses drives up your bounce rates.
Shockingly, 15% of email addresses on a typical list are invalid, yet 38.7% of senders rarely or never clean their lists.
"A really high bounce rate can ruin your sender reputation. Then your emails will be flagged as spam, which is obviously horrible, or even blocked, which is even worse." - Nicolas Palumbo, Marketing Director, Diversity Employment
High bounce rates don’t just result in failed deliveries - they can also trigger ISP scrutiny. ISPs monitor bounce rates as a measure of sender quality. A bounce rate over 2% raises red flags, and anything above 5% is a serious issue. When your rates cross these thresholds, ISPs may route your emails to spam folders or block them entirely.
"List hygiene maintains data quality, which ISPs consider when determining if emails are spam. Clean lists improve deliverability and increase engagement by reaching interested subscribers." - Jessica Materna, Director of Product and Partner Marketing, Litmus
To keep your list clean, remove inactive subscribers, use double opt-in processes for new signups, and rely on email verification tools to catch invalid addresses early. Addressing these issues is the first step toward reducing bounce rates and ensuring your campaigns reach their intended audience.
Email bounces can harm your sender reputation and impact your email campaigns. To keep bounce rates low, it’s essential to understand their causes and follow strategies that ensure reliable email delivery.
Email authentication is a critical step in protecting your emails from being flagged as spam. With over 3.4 million malicious emails sent daily, Internet Service Providers (ISPs) are vigilant about identifying unverified senders. Proper authentication reassures ISPs that your emails are legitimate.
Three key protocols form the backbone of email authentication:
p=none), quarantine (p=quarantine), or reject (p=reject) suspicious emails.
Platforms like Google and Yahoo require senders to implement SPF and DKIM, and if you’re sending more than 5,000 emails daily, DMARC is a must. A strict DMARC policy, such as p=reject, can improve deliverability by over 10% with major providers like Gmail.
To get started, configure a DMARC policy of p=none to monitor reports and confirm that SPF and DKIM are working correctly. Once everything is aligned, gradually transition to stricter policies like p=quarantine and eventually p=reject for maximum protection.
"The end goal is ideally a policy of p=reject. That's what DMARC is for. Ensuring that your domain cannot be spoofed and protecting our mutual customers from abuse." – Marcel Becker, Senior Director of Product at Yahoo
After setting up authentication, the next step is to validate your email list to catch potential issues before sending.
Email validation tools help identify and remove problematic addresses from your subscriber list. These tools check for issues like syntax errors, invalid domains, and inactive mailboxes, reducing the risk of bounces.
Popular platforms like ZeroBounce, NeverBounce, and Hunter can categorize email addresses into groups such as valid, invalid, risky, or unknown. Here’s what they typically detect:
Validation involves several steps. The tool first checks if the email format is correct, then confirms the domain exists and accepts mail. In some cases, it pings the mailbox to verify it’s active without sending an actual email.
Run a full validation on your list before launching major campaigns. For ongoing efforts, validate new signups in real time to prevent bad addresses from entering your database. Many validation tools offer APIs that integrate directly with signup forms, making this process seamless.
Keep in mind, no validation tool is perfect. Some may flag legitimate addresses as risky, while others might miss certain invalid ones. Testing multiple services can help you find the best fit for your audience.
Once your list is clean, maintaining it with best practices ensures long-term deliverability.
Proper email list management is essential to keep bounce rates under control. The industry standard for bounce rates is below 2%, but achieving this requires consistent attention to your list.
Double opt-in is one of the best ways to ensure high-quality subscribers. This method requires new users to confirm their email address by clicking a link sent to their inbox. While it may slightly reduce the number of signups, it ensures the addresses are valid and actively monitored, leading to better engagement and fewer bounces.
Regularly segment your audience to identify inactive subscribers. Try re-engaging them with targeted campaigns, but if they remain unresponsive, it’s better to remove them from your list. Persistently inactive addresses can turn into spam traps or abandoned accounts, which harm your sender reputation.
Set up automated rules to handle bounces. Remove hard bounces immediately and deactivate addresses after three consecutive soft bounces. Most email platforms have built-in tools to manage this, so review your settings to ensure they align with your sending frequency.
"Keep an eye on email addresses that consistently bounce. High bounce rates can harm your sender reputation, so it's crucial to manage and update your list accordingly." – Natalie Sullivan, Former Retention Marketing Manager, Avex Designs
When planning campaigns, segment your audience based on engagement levels. If you need to reach less engaged subscribers, limit that group to no more than 15% of your most active audience. This helps protect your overall sender reputation while giving you a chance to re-engage dormant contacts.
Avoid buying email lists at all costs. Purchased lists often include outdated addresses, spam traps, and people who never agreed to receive your emails. Building your list organically may take more time, but it results in better engagement and fewer bounces.
Lastly, make it easy for subscribers to update their information. Offer preference centers where they can adjust their email addresses or subscription settings. This proactive approach prevents bounces when users change jobs or switch email providers.
For businesses managing large-scale email operations, platforms like Infraforge offer advanced tools to maintain high deliverability rates. Features like dedicated IPs, automated DNS setup, and pre-warmed domains can help reduce bounce rates and scale your email campaigns effectively.
Your email infrastructure plays a huge role in reducing email bounces and maintaining a good sender reputation. By understanding and optimizing its components, you can improve deliverability and keep your email campaigns running smoothly.
Choosing between a dedicated or shared IP address can significantly impact your email deliverability and bounce rates. Each option has its own strengths and weaknesses, depending on your needs.
"Your email deliverability largely depends on whether you use a shared or dedicated IP." – Yevhenii Odyntsov, Content @Mailtrap
Shared IPs are cost-effective and ready to use right away. They pool multiple senders under one IP address, so you share the reputation with others. This can be great if the other senders are reputable, but risky if they’re not. Shared IPs are best for businesses sending less than 10,000 emails per day or those just starting out with email marketing.
Dedicated IPs, on the other hand, give you full control over your sender reputation. However, they require more effort and investment. You’ll need to carefully build and maintain your IP’s reputation through steady, consistent email practices. This option is ideal for businesses sending high volumes of emails or those needing complete control over their email operations.
| Feature | Shared IP | Dedicated IP |
|---|---|---|
| Setup | Ready to use immediately | Requires gradual warm-up and setup |
| Cost | Affordable, often part of basic plans | More expensive, an additional cost |
| Reputation | Shared among multiple senders | Exclusive to your business |
| Volume Requirements | Suitable for low to moderate volumes | Ideal for high-volume senders |
| Maintenance | Minimal effort required | Requires ongoing monitoring |
| Deliverability Impact | Affected by other senders | Full control over reputation |
The best choice depends on how many emails you send and the resources you have. If you’re sending smaller volumes or don’t have the expertise to manage an IP’s reputation, shared IPs are often the better choice. For low-volume senders facing deliverability issues, switching to a higher-quality shared pool can be more effective than moving to a dedicated IP. Keep in mind that major mailbox providers typically notice senders once they reach about 10,000 emails per day.
Next, let’s dive into how to build and maintain sender reputation using IP warming.
IP warming is a gradual process that helps you establish trust with Internet Service Providers (ISPs) when using a new or underused IP address. It’s all about starting small and scaling up strategically to build a positive sender reputation.
"IP warm-up is similar to a runner stretching before a marathon - it prepares the email system for optimal performance." – Samantha Stinn-Shelley, Contributor, Twilio
The process begins by sending small batches of emails to your most engaged subscribers - those who regularly open and interact with your emails. Over several days or weeks, you slowly increase the volume. For instance, you might start with a few hundred emails within 24 hours, focusing on subscribers who are likely to provide positive engagement signals like opens and clicks. This reassures ISPs that you’re a legitimate sender.
During the warming period, monitor key metrics like open rates, click-through rates, bounce rates, and spam complaints. If you notice any sudden spikes in negative metrics, it’s a sign you’re scaling too quickly. Adjust your sending schedule to maintain steady growth in reputation.
ISPs have daily sending limits, so it’s crucial to stay within those boundaries and maintain a predictable sending pattern. Regular, consistent sending - such as a few hundred emails per day for each ISP - helps establish trust. Engaging content like welcome emails, account confirmations, or special offers can further strengthen your reputation during this phase.
Once your sender reputation is established, transitioning to a private email infrastructure can take your deliverability to the next level.
For businesses managing large-scale email operations, private email infrastructure platforms like Infraforge offer advanced tools to keep bounce rates low and deliverability high. These platforms go beyond what traditional shared email services can provide.
Infraforge, for example, offers dedicated IPs, automated DNS setup, and pre-warmed domains to optimize your email performance. With features like SSL and domain masking, it helps protect your primary domain’s reputation. Multi-IP provisioning allows you to spread your sending volume across several IP addresses, improving deliverability.
Pre-warmed domains and mailboxes are a game-changer. Instead of starting from scratch with a cold IP, you can use domains with an established positive reputation, saving time and effort during the warming process.
This setup also gives you full control over your email configurations, storage policies, and security protocols - ideal for businesses handling sensitive data or operating under strict compliance rules.
With Infraforge’s API integration, you can scale your email campaigns programmatically, making it easier to manage multiple campaigns across different domains and IPs. The platform also integrates seamlessly with tools like Salesforge, offering a comprehensive solution for sophisticated email outreach.
The centralized Masterbox feature provides real-time insights into all email activity, helping you quickly identify and fix deliverability issues before they escalate. For businesses sending thousands of emails daily, this level of monitoring and control is essential for maintaining high deliverability rates and successful campaigns.
Private email infrastructure platforms provide the reliability and performance needed to scale your email operations effectively while keeping bounce rates under control.
Keeping an eye on your email bounce rates and addressing issues as they arise is essential for maintaining strong deliverability. With the right tools and strategies, you can identify problems early and take corrective action.
Email analytics platforms are invaluable for monitoring key metrics like open rates, click-through rates, bounce rates, and conversions. These tools provide a clear view of how recipients are engaging with your emails, helping you fine-tune your campaigns. Businesses using such platforms have reported response rates that are 32% higher compared to those that don't. Many of these tools also feature automated alerts to quickly flag unusual activity.
Specialized solutions like ZeroBounce (rated 4.7/5 on G2), NeverBounce (4.3/5), and Kickbox (4.5/5) focus on email verification and bounce tracking. Meanwhile, broader platforms like HubSpot Marketing Hub and ActiveCampaign integrate bounce tracking into their comprehensive campaign analytics suites. According to Google's guidelines, keeping spam complaint rates below 0.1% (preferably under 0.03%) and bounce rates at or below 0.3% is critical for maintaining optimal deliverability.
These tools and insights lay the groundwork for automating bounce management.
As email volumes grow, manually managing bounces becomes impractical. Automated systems step in to validate addresses, remove invalid ones, and handle both hard and soft bounces in real time. This is especially important given that subscriber data can deteriorate by around 22.5% annually.
Platforms like Infraforge offer advanced features for automated bounce management. For example, Infraforge uses multi-IP provisioning and a centralized Masterbox to distribute email volume across multiple IP addresses. This reduces the impact of bounce spikes on your sender reputation. Additionally, custom alerts and domain-wide insights help you act quickly when bounce rates exceed acceptable levels.
Automation can make a big difference. For instance, email marketing automation has been shown to increase revenue by up to 320%. In 2024, The Workplace Depot, a UK-based health and safety equipment provider, reduced its email bounce rates from 4.60% and eliminated spam complaints by using ZeroBounce to clean and segment their email lists. Features like verifying new subscribers, scheduling regular list cleanups, correcting typos in domain names, and setting up monitoring alerts are essential for effective automation.
But when automation isn't enough, there are additional steps you can take to address high bounce rates.
If your bounce rate goes above 2% - the industry standard threshold - you need to act fast to protect your sender reputation. For sudden spikes, investigate recent list imports, sending changes, or technical issues, and identify which emails are bouncing. If the increase is gradual, focus on regular list maintenance by removing inactive contacts, incorrect addresses, and unsubscribed users. Segmenting your audience to target highly engaged subscribers can also make a big difference.
"Keep an eye on email addresses that consistently bounce. High bounce rates can harm your sender reputation, so it's crucial to manage and update your list accordingly."
- Natalie Sullivan, former retention marketing manager at Avex Designs
Implementing double opt-ins is another effective way to minimize bounce rates. This process verifies new subscribers before adding them to your main list, ensuring their email addresses are valid. Additionally, proactive cleaning tools and re-engagement campaigns can help. For example, send a campaign to subscribers who haven’t interacted in the past 90 days, and remove those who remain unresponsive .
"If you're sending to less engaged subscribers, keep the volume below 15% of your most engaged subscribers. This will help your reputation remain positive."
- Tonya Gordon, manager of deliverability and compliance strategy at Klaviyo
On average, users of platforms like MailerLite maintain a bounce rate as low as 0.55%. Beyond bounce rates, tracking metrics like open rates, click-through rates, and spam complaints can give you a comprehensive view of your email campaign's health.
To effectively manage email bounce rates, you need a multi-layered approach that combines strong infrastructure, regular monitoring, and proactive list maintenance. Keeping your bounce rate below 2% is crucial for maintaining a solid sender reputation. As Christy Saia-Owenby, founder and CEO of MOXY Company, puts it:
"A bounce rate above 2 percent is concerning, and over 5 percent is problematic. Reduce it by using verified lists, authenticating domain records (SPF, DKIM, DMARC), and cleaning invalid addresses to avoid landing in junk boxes."
Maintaining a clean email list is essential. Use double opt-ins to confirm subscribers' interest and remove invalid addresses promptly. Hard bounces should be eliminated immediately, and addresses that soft bounce three times in a row need to be deactivated.
A robust email infrastructure is the backbone of good deliverability. Private email setups offer better control and performance. Platforms like Infraforge provide tools such as dedicated IPs, automated DNS configuration, multi-IP provisioning, and SSL-enabled domain masking. This setup not only improves visibility into email performance but also ensures security and isolation.
Poor deliverability isn’t just a technical issue - it’s a financial one. For instance, MailerLite users across all industries average a bounce rate of just 0.55%, which helps maximize ROI on email campaigns.
Deliverability is a direct reflection of your email program's health. Regularly review your domain, IP, and authentication settings to ensure everything is up to date. As Carin Slater from Litmus advises:
"Deliverability is a measure of the health of your email marketing program, so it's important to do regular check-ups on your domain, IP, and authentication in particular to make sure you're up-to-date, just like how we all go to the doctor each year."
SPF, DKIM, and DMARC are essential email authentication protocols designed to improve email deliverability and shield your domain from fraudulent activity.
SPF (Sender Policy Framework) allows domain owners to specify which mail servers are permitted to send emails on their behalf. This helps prevent email spoofing by ensuring unauthorized servers can't impersonate your domain. DKIM (DomainKeys Identified Mail) adds an extra layer of security by attaching a digital signature to your emails, verifying that the content remains unchanged during transit. DMARC (Domain-based Message Authentication, Reporting & Conformance) works alongside SPF and DKIM, instructing receiving servers on how to handle emails that fail authentication - whether to reject, quarantine, or allow them through.
Using these protocols not only strengthens your domain’s reputation but also reduces the risk of phishing attacks. Plus, it increases the likelihood that your emails will land in inboxes instead of being flagged as spam.
To reduce email bounce rates, businesses should prioritize keeping their email lists accurate and up-to-date. One effective method is implementing a double opt-in process, which ensures that subscribers confirm their interest in receiving your emails. This not only verifies email addresses but also helps build a more engaged audience.
It's equally important to regularly clean your email list by removing invalid or inactive addresses. This practice helps avoid hard bounces and keeps your list in good shape.
Another key step is authenticating your sending domains with SPF, DKIM, and DMARC protocols. These measures improve email deliverability and protect your domain from spoofing attempts. Finally, keep an eye on engagement metrics like open rates and click-through rates. Use this data to refine your email strategies and tailor your campaigns to your audience’s preferences. Together, these efforts will help your emails land in the right inboxes and maintain your sender reputation.
Using a dedicated IP for email campaigns can bring several benefits, such as improving email deliverability, giving you greater control over your sender reputation, and shielding your campaigns from the negative effects of other senders’ behavior on shared IPs. With a dedicated IP, your emails are evaluated based solely on your own sending habits, which helps lower the risk of being marked as spam.
Businesses should think about switching to a dedicated IP if they send a high volume of emails regularly, require dependable email authentication, or need to preserve a solid sender reputation for important campaigns. This approach is particularly useful for companies running large-scale outreach efforts or cold email campaigns, as it reduces the potential downsides of sharing an IP with others.