GMX, WEB.DE and mail.com · permanent error
554: HELO name changes or fails reverse lookup (554)
GMX refused the mail with a 554 because your server uses alternating HELO names, or its HELO name failed the reverse lookup.
- 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 Reject due to policy restrictions
What it means
Case r1002 is the same finding as case r1001, returned as a 554 rather than a 550: your server either announced different HELO names across connections or used a name whose reverse lookup failed. GMX asks for one stable HELO that complies with RFC 5321, meaning a fully qualified host name. The rejection is permanent, so the configuration has to change before the mail is sent again.
Common causes
- More than one machine or process sends through the same IP under different names.
- The HELO name does not resolve, or does not fit the PTR record of the IP.
- Unwanted software on the network sends mail under random names.
How to fix it
- 01Give each sending IP a single fixed HELO name in your domain.
- 02Align the HELO name with the A and PTR records of the IP.
- 03Block direct outbound mail (port 25) from machines that are not mail servers.
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 r1002: 554 Reject due to policy restrictionspostmaster.gmx.net
Related codes
- 550HELO name changes or fails reverse lookup.GMX refused the mail because your server announces different HELO names from one connection to the next, or the reverse lookup of its HELO name failed.
- 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.
- 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).
- 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.
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