Why Emails Bounce & 16 Ways To Reduce Bounce Rate

December 7, 2023 by
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Have you ever sent an email only to get a notification that it bounced back? It’s a common problem that can be confusing and annoying. Bounced emails can throw a wrench in your marketing strategy.

But why do emails bounce in the first place? And how can you prevent this from happening? This article demystifies the reasons behind email bounces. We’ll discuss various causes, from full inboxes and server issues to incorrect email addresses and spam filters.

Main Takeaways

  • The main causes of email bounces are non-existent recipients, blocked addresses, poor authentication, and spam-related issues.
  • There are two types of email bounces: Hard bounces and soft bounces. Hard bounces are a more difficult issue to fix and indicate a more complex problem.
  • To reduce your email bounce rate, make sure to regularly clean up your email list, avoid spammy content, and implement a double opt-in system.

What Is an Email Bounce?

An email bounce occurs when an email message gets rejected by a mail server, meaning it doesn’t reach the recipient’s inbox. Think of it as a digital “return to sender” note. Here’s a simple breakdown:

The Basic Concept: When you send an email, and it bounces, it means the email didn’t make it to the intended person’s email inbox. Instead, the email service provider sends it back to you, the sender​​.

How You Know It Happened: Generally, you’ll get an automated email from your email service provider. This message will tell you that your email couldn’t be delivered, and it might even give you a reason, like an invalid email address or a full mailbox​​​​.

Understanding email bounces helps you keep your email list clean and increases the chances that your messages will reach their intended recipients.

Types of Email Bounces

Email bounces fall into two main categories: hard bounces and soft bounces.

1. Hard Bounces

This type of email bounce usually indicates a permanent error in the email delivery process. Causes of hard bounces can include invalid email addresses, non-existent domains, or even a strict email security filter set by the recipient’s email provider.

Emails that hard bounce are often excluded from future email campaigns to protect the sender’s email reputation​​.

2. Soft Bounces

Soft bounces, on the other hand, are indicative of temporary problems with email delivery. These can be caused by issues such as a full recipient’s inbox, a temporarily down email server, or the email message being too large for the recipient’s inbox.

Soft bounces don’t necessarily imply a permanent delivery issue but rather a temporary glitch that might resolve itself in time​​​​​​.

Understanding these two types of email bounces is crucial for effective email management and marketing. By distinguishing between temporary and permanent delivery issues, you can make more informed decisions about your email campaigns and maintain a healthy email sender reputation​.

Why Do Emails Bounce? 

There is no set reason why emails bounce. Here are a few common issues that cause email bounces, organized into hard and soft bounces.

Hard Bounces

As mentioned earlier, hard bounces indicate a permanent issue with email delivery, leading to the email being undeliverable.

  1. Non-Existent Email Address: If an email address has typos, is missing information, or no longer exists, it results in a hard bounce. Regular verification of email lists and removal of invalid addresses are crucial to avoid this​​.
  2. Poor Email Authentication: Failures in complying with email authentication protocols (like DKIM, SPF, and DMARC) can cause hard bounces. Properly setting up these protocols and regularly checking for compliance issues is necessary​​.
  3. Fake or Incorrect Email Addresses: Sometimes, people provide fake email addresses, especially when asked in exchange for something online. Typos are also the most common cause of incorrect email addresses, leading to hard bounces​​.
  4. Email Blocked: If a recipient’s email server has stricter spam filter settings or if the sender’s domain is blocked (common in governmental or institutional domains), emails can hard bounce. In such cases, requesting the recipient to add the sender to their contacts may help​​.
  5. Recipient Email Server Completely Blocked Delivery: This can occur due to various reasons, including the security policies of the recipient’s email server​​.
  6. Spam or Reputation-Related Issues: When a sender’s domain has a low reputation or is listed on a major blocklist like Spamhaus, it can lead to hard bounces. Mailbox providers may permanently reject messages from such domains to protect their users from spam​.

Soft Bounces

Soft bounces are generally temporary and can be resolved over time:

  1. Full Inbox: When a recipient’s inbox is over capacity, incoming emails will bounce back until space is available. This could also indicate an abandoned email account​​​​​​​​.
  2. Server Overload: Emails can bounce back if the recipient’s email server is experiencing high traffic volumes or is temporarily down, such as during maintenance or crashes​​​​​​​​.
  3. Large Email Size: Emails that are too large for the recipient’s server to handle, often due to heavy attachments or images, can result in soft bounces​​​​​​.
  4. Email Filtering and Content Issues: Emails can bounce if they are filtered out by the recipient’s email server due to content, spam filters, or not meeting anti-spam, anti-virus, sender requirements, or DMARC policies​​​​.
  5. Temporary Server Error: General network outages or temporary server issues can lead to bounces. Resending the email usually resolves this issue​​​​.
  6. Vacation/Auto-Reply: When someone sets an auto-reply (e.g., for vacations), emails might bounce back, although they are still delivered to the inbox​​​​.
  7. Suspended Accounts: Email addresses that repeatedly bounce across various campaigns may be categorized as suspended. If this happens, it typically indicates a broader issue with the email account​​.
  8. Content-Related Soft Bounces: Mailbox providers might bounce emails that appear suspicious due to their content or links. These bounces can be upgraded to hard bounces if the issue is not resolved, indicating problems with the email’s content or the sender’s reputation.
  9. Miscellaneous Reasons: Sometimes, emails bounce for unspecified reasons. It’s important to monitor such bounces to determine if they are recurring and take appropriate action​​​​.

How Do Email Bounces Impact Sender Reputation and Deliverability?

Your sender reputation is extremely important for your marketing campaigns. Email bounces are critical in determining a sender’s reputation and email deliverability. Understanding their impact is vital for effective email marketing.

Impact on Sender Reputation

Email bounces, especially high hard bounce rates, send a negative signal to the sender’s server. Hard bounces occur when messages are sent to invalid email addresses, which can mark the sender as spam and lead to potential blocking by Internet Service Providers (ISPs). 

This, over time, lowers the sender score, making it more likely for emails to end up in spam folders or not be delivered at all.

Effect on Email Deliverability

High bounce rates negatively impact deliverability. Email Service Providers (ESPs) use sender reputation scores to decide if your emails make it to the inbox. A poor reputation, often due to high bounce rates, triggers spam filters. 

This makes your emails less likely to be seen by your recipients, sometimes landing them in spam folders or not being delivered.

Combined Score of IP and Domain Reputation

Your email sender reputation is a combined score of your IP and domain reputation. The IP reputation is based on the IP address used for sending emails, while the domain reputation measures how trustworthy your domain is. 

Both these aspects heavily influence how mailbox providers view your credibility.

Metrics Affecting Sender Reputation

Other than bounce rates, sender reputation is affected by the volume and frequency of sent emails, engagement metrics like click and open rates, unsubscribe rates, spam complaints, and being listed on email blacklists. 

Poor performance in these areas can worsen the sender’s reputation, reducing email deliverability.

Bounce Rate Thresholds

Ideally, bounce rates should be below two or three percent. When bounce rates climb above five percent, ESPs may penalize the sender’s reputation more harshly. This high rate suggests to ESPs that the sender might be using poor tactics or sending low-quality lists.

Triggering Email Filters

A poor sender reputation can set off email filters. Before delivering emails, they undergo spam filtering based on the sender’s reputation and other factors. Emails categorized as spam often land in the recipient’s spam folder, reducing the campaign’s effectiveness.

What Is a Good Email Bounce Rate?

A good email bounce rate is a critical measure for evaluating the effectiveness of email marketing campaigns. Here’s a summary of what constitutes an acceptable email bounce rate:

A universally accepted benchmark across various industries suggests an email bounce rate below 2% is generally considered normal. If the bounce rate falls between 2% and 5%, it should be seen as a warning sign, indicating potential issues that need addressing. 

Any rate above 5% is deemed critical and requires immediate intervention to address underlying issues, such as problems with the email list or targeting strategies​​. 

Different industries have varying standards for what constitutes an acceptable bounce rate. These variations are due to differences in target demographics, geographical locations, and the specific behaviors of customer segments in each industry. 

What is considered a good rate in one industry might not apply to another, making it important to understand and adhere to industry-specific benchmarks​​​​​​.

How to Calculate Email Bounce Rate

To calculate the email bounce rate, divide the total number of bounced emails by the total number of emails sent, and multiply the result by 100. This calculation helps quantify the rate and understand its impact on email marketing effectiveness.

16 Ways to Reduce Email Bounce Rate

So, now you know that when emails bounce, it can have a negative impact on your email’s reputation and cause fewer emails to reach their destination. But how do you reduce email bounces?

1. Double Opt-Ins

Implementing a double opt-in process is a robust measure. It ensures that you are adding only valid and active email addresses to your list. This process involves sending an authentication email to every new subscriber and adding them only after they confirm their subscription​​.

2. Regularly Clean Your List

It’s essential to periodically remove inactive accounts and problem recipients from your email list. Start by eliminating inactive users and those who haven’t engaged with your emails for a while. You can also run campaigns targeting disengaged contacts to confirm their interest in receiving your emails​​.

3. Avoid Spammy Content

Ensure your emails don’t trigger spam filters. Avoid using overly large or small images and phrases typical in spam emails. Pay attention to your email’s format, content, and layout.

4. Segment Your List

Segmenting your list ensures that subscribers only receive relevant information. This strategy can reduce the likelihood of your emails being marked as spam or blacklisted. Group your most active subscribers and engage them more frequently while attempting to re-engage inactive ones​​.

5. Use a Professional Email Domain

Avoid using free sender domains like Gmail or Yahoo for your business emails. Sending emails from an owned domain adds legitimacy and reduces the chances of your emails hitting the spam folder​​.

6. A/B Test Your Emails

Test different elements of your emails, like subject lines, email copy, and calls to action (CTAs), to see which versions perform best. This helps you refine your approach for better engagement​​​​.

7. Remove Hard Bounced Addresses

Regularly remove hard-bounced email addresses from your list. These addresses are either incorrect or inactive, and keeping them can inflate your bounce rate unnecessarily​​.

8. Implement a Good Captcha System

Using a captcha on your signup forms can prevent bots or spam accounts from being added to your email list, ensuring that only real, interested people sign up​​.

9. Create Relevant Opt-Ins

Offer incentives like ebooks, checklists, demos, or special offers highly relevant to your target audience. This ensures you attract high-quality subscribers who are likely to engage with your emails​​.

10. Keep Your List Updated

Regularly ask your subscribers to inform you of any changes to their email addresses. This practice helps maintain a list full of active accounts​​.

11. Provide Value in Your Emails

Write content that is valuable and relevant to your subscribers. This encourages them to look forward to and engage with your emails, reducing the likelihood of bounces​​.

12. Ensure Subscribers Want Your Emails

Make sure your subscribers have explicitly opted in to receive your communications. This reduces the chances of sending emails to uninterested parties and subsequently facing bounces​​.

13. Offer Hyper-Focused Opt-Ins

Create opt-ins that are precisely targeted to your audience’s interests. This helps get subscribers more likely to be active and engaged​​.

14. Follow-up with Subscribers

Regularly check in with your subscribers to gauge their interest in your emails. This can involve asking for feedback or sending re-engagement campaigns​​.

15. Use Verified IP Addresses and Domains

Send your emails from verified IP addresses and domains. This adds credibility and can significantly improve your email deliverability​​.

16. Improve Email Deliverability

Focus on overall strategies to enhance email deliverability, such as optimizing email content, adhering to sending best practices, and using reliable email service providers​​.

By implementing these strategies, you can effectively reduce your email bounce rate, enhancing the success and deliverability of your email campaigns.

Should I Delete Bounced Emails?

Yes, you should delete bounced emails from your list, but with consideration for certain factors. Here’s a detailed explanation:

Hard Bounces: It’s best to remove these immediately from your list, as keeping them can hurt your sender score, making it harder for your emails to reach people who want to hear from you​​​​.

Soft Bounces: Soft bounces should be monitored, as they might resolve on their own. It’s not necessary to remove these contacts immediately​​​​.

Reasons for Deletion

List Hygiene: Deleting hard bounced emails keeps your list clean and efficient. This can also help avoid potential GDPR violations with contacts you no longer use​​​​.

Irrelevance: If you no longer need certain contacts or they’re unsubscribed, deleting them can simplify your list management​​​​.

Considerations Before Deletion

Potential Recovery of Contacts: Some contacts might update their email addresses or subscription preferences. If you’re communicating with them on different channels or they are involved in ongoing deals, consider keeping them​​.

Impact on Contact Limits: Bounced or unsubscribed contacts typically don’t count towards your contact limit, so there’s no cost burden in keeping them​​.

Data Loss: Deleting contacts results in losing all past statistics and contact history associated with them. This information will also be removed from all campaign reports​​. Therefore, it might be wise to export these contacts into a CSV file before deletion for record-keeping​​.

Minimize Your Bounced Emails

To sum up, dealing with bounced emails can be a hassle, yet you can often avoid them. Simple steps like double-checking email addresses, writing concise messages, and avoiding spam-like content greatly reduce the likelihood of bounces. 

Considering that about 9.96% of emails across various industries bounce back, handling these issues is vital for the success of your email campaigns. Effective email communication and successful cold outreach campaigns are essential in today’s fast-moving digital world, and managing bounces plays a big part in this.



About The Author

Mike Yon

Mike is the Co-Owner of Growth List.

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