Handling High Bounce-Back Rates (Error Addresses)

In the world of email, "bounced" means that the email never reached the recipients inbox. It's important to understand that with email, bounces are unavoidable. However, while some bounces can be avoided, some cannot; it's important to know the difference.

Note: Also check out Deliverability Best Practices for even more important guidance on getting the most from your campaigns and mailings.

Bounce types

Soft bounces come back with a three-digit response code that starts with a 4. These are usually temporary failures, for example due to a full mailbox or power outage. Since soft bounces are considered temporary, delivery is reattempted over a 30-hour period. Email addresses that are still bouncing after four attempts will be marked as a soft bounce, and no further attempts will be made for that campaign. Addresses marked as a soft bounce remain an Active contact in your audience unless it soft bounces four times in a row. At this point, it will be moved to Error status and not included in future sends.

Hard bounces come back with a three-digit response code that starts with a 5. Hard bounces are permanent obstructions to email delivery, such as a nonexistent email address, a block due to content, or the server is rejecting your email as junk or spam. Hard bounces are considered invalid and are immediately moved to Error status. These email addresses won't be sent again unless you reactivate them.

Bounce rate benchmarks

2% or lower: Soft bounces are probably a temporary issues, but hard bounces may indicate you are sending to old lists or you have a spam-bot problem on one of your signup forms. Continue to keep an eye on it to see if you notice a trend.

2-5%: Look into this for possible changes in your sending or content habits. Also review your list to make sure it isn't filled with old, inactive subscribers, as they will hurt deliverability.

5-10%: Verify that you didn't accidentally re-enable old addresses or lists. Double-check that all signup forms are secured with some form of reCAPTCHA.

10% or higher: Verify that your authentication records are current and valid and that no major changes have occurred in your domain. We recommend discontinuing your mailings until you resolve the issue going forward.