Hard Bounce Permanent delivery failure
Meaning
A hard bounce is an email that has failed to deliver for permanent reasons, such as the recipient's address being invalid or the domain not existing.
Common causes
- The recipient's email address does not exist (typo or deleted account).
- The destination domain does not exist.
- The receiving server has permanently blocked delivery.
How to fix
- Immediately remove hard bounced email addresses from your mailing list.
- Implement double opt-in to prevent invalid addresses from entering your list.
- Regularly clean your email list to remove inactive subscribers.
Provider notes
Amazon SES. SES requires you to keep your hard bounce rate below 5% (and ideally below 2%). Exceeding this can lead to account suspension.
Example bounce
550 5.1.1 The email account that you tried to reach does not exist.
FAQ
- Should I ever retry a hard bounce?
- No. Retrying hard bounces tells ISPs that you do not maintain your list, which will severely damage your sender reputation.
- How do hard bounces affect deliverability?
- High hard bounce rates signal to mailbox providers that you are a spammer or have poor list acquisition practices, causing your emails to be routed to the spam folder.
Written walkthrough
- How to Get Alerted When Your Amazon SES Bounce Rate Spikes By the time you see bounces climbing in the SES console, the damage is often done. Here's how to put a CloudWatch alarm on your reputation metrics so you hear about it first — and why the alarm is a floor, not the whole picture.
- Amazon SES Paused My Sending: How to Fix Bounce and Complaint Rates SES paused your account over bounces or complaints. Here are the thresholds, why each number climbs, how to bring it back down, and how to write the remediation plan AWS actually accepts.