550 5.7.25 The IP address sending this message does not have a PTR record
The sending IP has no reverse DNS
Seen in Gmail bounces
Gmail requires the sending IP to have a PTR record that resolves back to the same IP.
Common causes
- A server or VPS sending mail directly without reverse DNS set.
- A PTR that doesn't resolve forward to the same IP.
How to fix it
- Ask your hosting or IP provider to set a PTR (e.g. mail.example.com).
- Make sure that name has an A/AAAA record pointing back to the IP.
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Related errors
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- 550 5.7.606 Access denied, banned sending IP · Microsoft banned the sending IP address