I am using the following setup: Server A: website + full virtualmin, Dovecot disabled. Server B: Exchange mail server from outlook. I configured the DNS so the mail points to the outlook servers.
Problem: Whenever I send an e-mail from the server to a user that has an e-mail address with any domain that is hosted on that server I get an error 500: user does not exist.
What happens: I send the mail from the website (drupal, mail() function) to a user. Postfix grabs the e-mail and wants to deliver on the same server (A), while, according to the DNS, it should be delivering it to the exchange server (B).
What am I missing here?