I’m not sure whether I’m blind and can’t find it or if its not supported.
I basically want one email that receives every single mail, even the ones I have a mailbox for already.
If that doesn’t work, is there a different notification possibility?
As far as I know email servers in general don’t support this as it is a major privacy issue!
A potential work around is to create an alias for the mailboxes you have already delivering to the catchall address as well as the actual mailbox. But you will need to create one for every single mailbox, in addition to the general catchall for unmatched addresses.