Mail log entry, from where?

SYSTEM INFORMATION
OS type and version Ubuntu 22.04
Webmin version 2.105

I have 2 entries in the mail log that I have no clue where they come from

two000backups@vmi1498586.contaboserver.net

status=bounced (mail for vmi1498586.contaboserver.net loops back to myself)

two000backups is the owner Virtualmion creates. the domain vmi1498586.contaboserver.net is the domain the VPS comes with. But I have changed bost hosts and hostname and also hostname in main.cf. I cant think of any more places where this can come from

Any hints?

That usually happens if you’ve got a virtual/alias or something that has the same name as the hostname of the system. But, if you’ve changed the myorigin, mydomain, mydestination, myhostname etc. from the defaults, you can get surprising results.

This may help, myhostname was the issue in the forum.