Gmail sending IP rejection
Gmail 550 5.7.25: This message was blocked because the sending IP address doesn't have a PTR record, or forward DNS doesn't reference the sending IP address
The public IP that connected to Gmail has no PTR record, or its PTR hostname does not resolve back to that IP.
The Gmail response is:
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 reference the sending IP address.
Enter your domain and sending IP. MailFixIt checks PTR and forward DNS automatically and shows the evidence.
SMTP 550 is permanent for this attempt. Configure matching reverse and forward DNS, then send a new message.
Fix reverse DNS
- Copy the actual public sending IP from the Gmail response or outbound log.
- Query PTR for that IP.
- Choose a stable mail hostname you control.
- Ask the IP owner to set PTR to that hostname.
- Publish an A or AAAA record that maps the hostname back to the same IP.
- Verify both directions, then send a new message.
If you use hosted email
Open a support case with the sending provider. Do not change unrelated records in your domain’s normal DNS zone; the provider controls PTR for its IP.
Frequently asked questions
Who can change PTR?
Usually the VPS, cloud, hosting, or network provider that owns the sending IP. Your normal DNS provider often cannot change it.
What must match?
The sending IP must resolve by PTR to a hostname, and that hostname’s A or AAAA record must include the same IP.
Related email diagnostics
Gmail 451 4.7.26: Unauthenticated email is not accepted due to DMARC policy, but temporary DNS failures prevent authenticationFix Gmail 451 4.7.26 by checking temporary DNS failures and restoring aligned SPF or DKIM without weakening DMARC.
Gmail 550 5.7.29: This message was blocked because it wasn't sent over a TLS connectionFix Gmail 550 5.7.29 by restoring TLS on the final SMTP connection to Gmail.
Primary sources: Gmail SMTP errors and codes, Google email sender guidelines.