IONOS (1&1) · permanent error
554: no 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).
- 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 Invalid DNS PTR resource record
What it means
Reverse DNS maps an IP address back to a name through a PTR record. IONOS requires one for every server that delivers mail to its customers. This 554 means your sending IP has none, so the mail is refused. The remedy IONOS gives is short: add the missing DNS entry. The PTR record is managed by whoever owns the IP range, usually your hosting provider or ISP, not in your domain DNS. Choose a name in your own domain that resolves back to the same IP.
Common causes
- No PTR record was created for the sending IP.
- The server moved to a new IP and reverse DNS was not set up for it.
How to fix it
- 01Ask the owner of the IP range (your host or ISP) to add a PTR record for the IP.
- 02Use a fully qualified name in your domain, such as mail.yourdomain.tld, that resolves back to the IP.
- 03Retry delivery once the record is published.
Sources
What this page rests on, checked on 20 Oct 2026. The explanation is ours; the reply text is the server's.
Related codes
- 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.
- 554No 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.
- 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.
Further reading
All 17 IONOS codesEvery code in the wikiPaste your own bounce