Hi everybody, My host relay is working but I was aksed to add a new domain (like external.example.com). I have added in main.cf the new fqdn in relay_domains relay_domains = $mydestination, example.com,example2.com, externe.example.com and in transport example.com smtp:[192.168.1.22] example2.com smtp:[192.168.1.22] external.example.com smtp:[192.168.1.22] Mails sent to users with example.com and example2.com domain are well delivered. But for mails to external.example.com i got this message Mar 17 16:47:52 relayhost postfix/smtp[11948]: 754E1876A01: to=<[email protected]>, relay=relayhost2.example.com[80.81.82.83]:25, delay=19555, delays=19525/0.01/30/0, dsn=4.4.6, status=deferred (mail for external.example.com loops back to myself) I read another Q/A about the same issue right here, but it's not helping me. Can you ?