You are right, I do want the temporary mail to go into the users main mailbox (I just don’t know how to set this up).
So I take it, if I remove the “another domain” as a normal domain from mailcow, I will be able to add it as an alias domain?
Yes, it is a valid domain and it is added to mailcow like the first domain. I could set up mailboxes for it. From Ares’s response in this thread I understand, however, that this is not the right way to go about this…
Does this explain my problems with setting up an existing user as the domain administrator?