554: no reverse DNS for your IP
GMX refused the connection because the IP address of your mail server has no PTR record, so it is not tied to any domain name in DNS.
- GMX, WEB.DE
- Provider
- Permanent (5xx)
- Class
- Sources checked
- Author
At a glance
- Code
- 554
- Provider
- GMX, WEB.DE and mail.com
- Temporary or permanent
- PermanentRefused for good: the message comes back to the sender, and resending it gets the same answer.
- Who has to act
- The sender. The fix is on the sending side: your domain, your server or your list.
- What the server says
554 Invalid DNS PTR resource record
What it means
Case r0602 means GMX looked up the reverse DNS of your sending IP and found no name at all. GMX requires every mail server to have a PTR record, and it refuses the connection with 554 when there is none. Adding the record fixes it, but GMX adds two warnings. A generic provider default will still be rejected (that is case r0601), so the name should be your own, such as mail.yourdomain.tld. And if a PTR record already exists and the rejection continues, the cause may be a DNSSEC signing error on the reverse zone, which makes the record unusable.
Common causes
- No PTR record was ever created for the IP.
- The reverse zone is delegated to a name server that does not answer for it.
- A DNSSEC signing error on the reverse zone makes the existing record fail validation.
How to fix it
- 01Ask whoever controls the IP range (your host or ISP) to create a PTR record for it.
- 02Use a fully qualified name in your own domain, such as mail.yourdomain.tld, not the provider default.
- 03Make that name resolve back to the same IP.
- 04If a record already exists, check the DNSSEC signatures of the reverse zone.
Sources
What this page rests on, checked on 20 Oct 2026. The explanation is ours; the reply text is the server's.
- GMX Postmaster case r0602: 554 Invalid DNS PTR resource recordpostmaster.gmx.net
Related codes
- 554Reverse DNS does not meet GMX requirements.GMX refused the connection because the reverse DNS (PTR) record of your IP looks generic or dynamic. GMX expects a fixed IP with its own mail host name.
- 421Reverse DNS lookup failed for now.GMX could not look up your IP address reverse DNS because of a temporary DNS error, so it deferred the connection. Your server's retry usually succeeds.
- 554No reverse DNS for your IP.IONOS refused your mail because the IP address of your mail server has no domain name assigned to it in DNS (no PTR record).
- 554Transaction failed.The server permanently refused the transaction, often after receiving the message data or straight away when the connection opened.
554 at other providers
- 554Permanent rejection (554).Yahoo or AOL rejected the message for good with a 554. Yahoo uses this code for several problems, from failed authentication to unacceptable content, so the wording of the reply tells you which.
- 554Failed authentication.Yahoo or AOL refused the message because it failed the checks that confirm the sending domain, such as DKIM against the domain's policy. Yahoo lists this among its permanent 553 and 554 errors.
- 554Recipient does not exist.The Yahoo or AOL account you wrote to does not exist. The failure is permanent: check the address with the recipient, and remove it from any list.
- 554No reverse DNS (PTR) record.Xfinity refused the connection because your sending IP has no PTR record. Every server sending to Xfinity needs valid reverse DNS, so the owner of the IP must add one.
- 554Reverse DNS does not meet IONOS policy.IONOS refused your mail because the PTR record of your IP does not meet its policy, typically a generic or dynamic-looking provider name.
Further reading
All 57 GMX, WEB.DE codesEvery code in the wikiPaste your own bounce