550 5.7.25: Reverse DNS (PTR record) missing
The IP address that sent the message has no matching hostname in reverse DNS, so Gmail treats it as untrustworthy.
Blocked The address is probably fine. The problem is how the mail was sent.
What the bounce message looks like
The wording changes from one provider to another. These are typical examples:
550 5.7.25 This message was blocked because the sending IP address doesn't have a PTR record, or the forwarding DNS entry doesn't point to the sending IP. (Gmail)Common causes
- A self-hosted mail server on a new VPS or cloud server
- A home or office internet connection sending mail directly
- A PTR record that doesn't match the server's hostname
How to fix it if you sent the email
- If you use an email provider, contact them.
- If you run your own server, ask your hosting company to set a PTR record for the IP that matches your mail server's hostname.
If you manage the receiving or sending mail system
- Set reverse DNS for the sending IP and make sure the hostname resolves back to the same IP.
Free tool: paste the full bounce into the bounce message decoder to get a plain-English reading of every code in it.
Questions people ask
- What does 550 5.7.25 mean?
- The IP address that sent the message has no matching hostname in reverse DNS, so Gmail treats it as untrustworthy.
- Is 550 5.7.25 a hard or soft bounce?
- Blocked. The address is probably fine. The problem is how the mail was sent.
- Should I remove the address after a 5.7.25 bounce?
- No. Fix how the mail is sent; the address itself is probably fine.