Fedora 15/ISPconfig-3 email problem.
Getting this message sent to root about firstname.lastname@example.org
(reason: 550 5.1.1 <email@example.com>: Recipient address rejected: User unknown in local recipient table)
I found that somehow saslauthd was not running. So I started it and I'm no longer getting the error but the emails are now going to the queue.
Hope this helps someone.