Issue Postfix delivers mail as if a domain was an alias, but it is not

[romofoos]

Server operating system version

Almalinux 9.4

Plesk version and microupdate number

Version 18.0.66 #2

I have a subscription aaa.com
Within the subscription a few 100 domains, bbb.com, ccc.com etc. All domains have been added as domain. Mail-service on bbb.com, ccc.com etc is 'not configured'
There are NO aliases for aaa.com

When i send a mail from my server to an address like [email protected], [email protected], the mail does not leave the server, but it is delivered to an address on my server [email protected].
As if bbb.com, ccc.com were aliases for aaa.com, which they are not

If i enable mail for bbb.com, and next disable mail for bbb.com (not configured), the problem disappears for this domain bbb.com

What is going on here?

 

[Sebahat.hadzhi]

Hello, @romofoos . Could you please navigate to Domains > bbb.com > Mail > Mail Settings, and confirm what is the option selected for "What to do with mail for non-existent users"?

 

[romofoos]

So mail for bbb.com is set to 'not configured' and the option for non-existent users is 'reject'

 

[Sebahat.hadzhi]

Thanks for the confirmation. Please also check what's the setting for the service plan assigned to that subscription - Service Plans > service plan name > Mail > Policy on mail for non-existent users. If that's set to anything different than "forward to [email protected]" I would suggest getting in touch with our support team for further investigation.