554: too many copies of one header field
GMX refused the message because one header field, such as DKIM-Signature, List-Unsubscribe or Resent-From, appears more often than GMX accepts.
- 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 Transaction failed
What it means
Some header fields may legally appear several times, but GMX caps how many it accepts. These cases name the field over the threshold: DKIM-Signature (r0709), the mailing list fields List-Archive, List-Help, List-Id, List-Owner, List-Post, List-Subscribe and List-Unsubscribe (r0715 to r0721), and the Resent fields Resent-Cc, Resent-Date, Resent-From, Resent-Sender and Resent-To (r0726 to r0730). The case pages do not give the thresholds. Repeated copies usually build up when a message passes through several lists, forwarders or signing services.
Common causes
- The message was forwarded or resent many times, adding Resent fields at each step.
- Several mailing lists or list tools each added their own List headers.
- Several services in the sending path each added a DKIM signature.
How to fix it
- 01Read the GMX case number to see which field is over the limit.
- 02Look at the raw headers and find which systems add the extra copies.
- 03Configure the sending path so each field is added once, for example a single List-Unsubscribe and only the DKIM signatures it needs.
- 04Send the message again.
Sources
What this page rests on, checked on 20 Oct 2026. The explanation is ours; the reply text is the server's.
Related codes
- 554A header field appears more than once.GMX refused the message because a header that RFC 5322 allows only once, such as From, Date, Subject or Message-Id, appears more than once.
- 554DKIM-Signature header has invalid syntax.GMX refused the message because its DKIM-Signature header does not follow the syntax that RFC 6376 defines for it, so the header itself is malformed.
- 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.
Further reading
All 57 GMX, WEB.DE codesEvery code in the wikiPaste your own bounce