Additional email address per user account support

Im not sure if im in the correct topic, let me explain the case:

Actually I’m having difficulties to whitelist the domain in http://matrix.spfbl.net/en/138.68.75.234

Basically, they attempts to send an email to postmaster@forum.example.com, but this address doesn’t exist and is not managed (I used this setup Straightforward direct-delivery incoming mail ), so it is received as “rejected” (but seems like it is cut?)

How i can make it to be a real address, or to be forwarded to a specific “admin of the forum” address? I would need to add an additional address to my user profile?