554: rejected under IONOS policy
IONOS refused the mail because it violates IONOS policy, most often because the sending server is mainly sending spam.
- IONOS
- Provider
- Permanent (5xx)
- Class
- Sources checked
- Author
At a glance
- Code
- 554
- Provider
- IONOS (1&1)
- 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
IONOS uses this 554 when a message breaks its policy, and the help page names the usual reason: the sending server is mostly sending spam. It is a judgement about the traffic from your server as a whole, so resending the same mail will not help. IONOS asks senders to contact it to have the case examined. Before that, find out why your server looks like a spam source: compromised accounts, a form or script sending on its own, or bulk mail to people who did not ask for it.
Common causes
- Most of the mail from your server is spam, or looks like it to IONOS filters.
- An account or script on your server was compromised and sends spam.
- Bulk mail went to recipients who never agreed to receive it.
How to fix it
- 01Check the outbound queue and logs for spam or unexpected volume, and stop the source.
- 02Secure compromised accounts and forms.
- 03Send bulk mail only to recipients who opted in.
- 04Contact IONOS to have the case examined, quoting the full error.
Sources
What this page rests on, checked on 20 Oct 2026. The explanation is ours; the reply text is the server's.
Related codes
- 550Spam domain or invalid HELO.IONOS refused the mail because your sender domain is known as a spam domain, or because your server HELO/EHLO is not a fully qualified domain name.
- 554Headers break RFC 5322.IONOS refused the message because its headers do not follow RFC 5321 and RFC 5322: a missing or doubled Date, or a From, Sender, To, Cc or Subject header that is repeated or malformed.
- 554System and domain suspended for spam.GMX permanently refused your mail after a massive amount of spam reached its customers through your mail system and domain, and suspended their privileges.
- 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.
- 554Rejected for breaking GMX guidelines.GMX refused the message permanently because the connection broke its guidelines. GMX points to its requirements page and asks for the full error message if the problem continues.
- 554IP address on the GMX blocklist.Your sending IP is on a blocklist that GMX manages itself, so its servers refuse the connection. GMX keeps a strict no tolerance policy toward spam.
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