550-5.7.25: Missing PTR (reverse DNS) record

GmailSMTP

The error usually looks like this:

550-5.7.25 The IP address sending this message does not have a PTR record setup, or the corresponding forward DNS entry does not point to the sending IP.

What it means

The sending server’s IP address has no reverse DNS (PTR) record, or it doesn’t match the server’s hostname.

Common causes

  • Reverse DNS has not been configured for the mail server’s IP address.

How to fix it

  1. Ask your hosting or internet provider to set a PTR record for the IP address, matching a hostname whose A record points back to the same IP.

Tools to help diagnose it

Email blacklist checker

Check whether a mail server IP address or domain is listed on common email blocklists

SPF, DKIM, and DMARC checker

Check your domain’s email authentication DNS records, count SPF lookups and diagnose deliverability issues

A free tool provided by Auth-Email

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Read the docsTry Auth-Email →

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