Your own server gave up after retrying for a long time (often 1–5 days) because it kept getting temporary errors or could not connect.
Hard bounce · permanent
Common causes
- The recipient server was down or unreachable
- Repeated temporary deferrals (rate limits, greylisting that never cleared)
- Your server cannot connect out on port 25
How to fix it
- Look at the earlier temporary errors in the bounce for the real cause
- Test the recipient's mail server with the SMTP Tester
- Check that your host allows outbound port 25
SMTP TesterRun the right check for your domain or paste the full bounce message for a precise explanation.
Open SMTP Tester →Frequently asked questions
Why did my email bounce days later?
Because the server kept retrying a temporary error and finally gave up.