554 (NOWL) — None/bad reputation, contact for reset (T-Online)
Retrying will not help. The message will not be delivered.
The reply
554 IP=<IP> - None/bad reputation. Ask your postmaster for help or to contact tobr@rx.t-online.de for reset. (NOWL)T-Online does not recognise your sending IP, or has formed a poor opinion of it. Unusually among receivers, the reply tells you exactly where to write for a reset — and that request is normally granted.
What it means
"None" is the important half: it is not necessarily that your reputation is bad, but that T-Online has none on file for this address. The provider treats unknown IPs as untrusted rather than neutral, so a new sending address is refused until it is registered with them. The reset request in the reply is the intended route, not a last resort.
Why it happens
- A new sending IP T-Online has never seen.
- An IP whose reputation with them has degraded through complaints.
- Missing or mismatched reverse DNS on the sending IP.
- A range T-Online treats with suspicion, including many cloud providers.
What to do
- Write to tobr@rx.t-online.de, as the reply says, with the sending IP, its reverse DNS name, who you are and what you send. This is the documented route.
- Set correct forward-confirmed reverse DNS before you write — they check it.
- Publish SPF, DKIM and DMARC for the sending domain.
- Register at postmaster.t-online.de for ongoing visibility.
- Ramp volume gently after the reset rather than resuming at full rate.
Questions
Is emailing tobr@ really the fix?
Yes. T-Online is one of the few providers that names a working address in the rejection itself, and the reset is routinely granted for legitimate senders with correct reverse DNS.
What does "None" mean?
That they hold no reputation for the IP at all. A brand-new address is not neutral to T-Online — it is untrusted until you introduce yourself.