554: A header field has invalid syntax
GMX refused the message because a header, such as Date, From, Sender, Subject or To, is not written the way RFC 5322 and RFC 2047 require.
- 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
GMX checks the syntax of key header fields. These cases name the field that failed: Date (r0704, RFC 5322 section 3.3), From (r0710), Sender (r0731), Subject (r0733), To (r0735), or the x-tdid field (r0737), which must be valid UTF-8. For address fields GMX gives the correct form, such as From: "Sender name" <sender@example.com>. Non-ASCII characters, accents and symbols included, must be MIME encoded under RFC 2047. The message is refused with 554 until the field is corrected.
Common causes
- A Date header in a non-standard format, such as a local date style.
- A display name with accents or symbols written raw instead of RFC 2047 encoded.
- An address field with missing angle brackets, stray quotes or several addresses run together.
- A header containing bytes that are not valid UTF-8.
How to fix it
- 01Read the GMX case number to see which field failed.
- 02Compare that field in the raw message with the form RFC 5322 gives, for example Date: Sat, 1 Jan 2000 12:00:59 +0200.
- 03Encode non-ASCII display names and subjects with RFC 2047, which mail libraries do for you.
- 04Fix the software that writes the header and send again.
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 r0704: 554 Transaction failed (Date syntax)postmaster.gmx.net
- GMX Postmaster case r0710: 554 Transaction failed (From syntax)postmaster.gmx.net
- GMX Postmaster case r0733: 554 Transaction failed (Subject syntax)postmaster.gmx.net
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.
- 554Required Date or From header is missing.GMX refused the message because it has no Date header or no From header, both of which RFC 5322 requires in every message.
- 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
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