I was running portupgrade -a on my FreeBSD machine when I discovered some problems. The first problem had to do with the size of my mail queue. I kept getting a "452 Insufficient system storage" message from Microsoft Outlook, along with an error code of 0x800CCC0F. I am running Postfix, and so had to edit main.cf to read:
message_size_limit = 51200000
mailbox_size_limit = 51200000
queue_minfree = 102400000
Those sizes may seem rather large, but I've got room to spare. This got rid of the "Insufficient storage" errors, but then I got a new error. Outlook said that the connection to the mailserver was "unexpectedly interrupted" when trying to receive mail. This was a problem with my POP3 daemon. I wasn't unable to telnet to port 110, so it seemed like it wasn't running. I use Courier-IMAP, which comes with a POP3 daemon. I tried to rebuild the port, but it complained that the port was broken. So I had to figure out how to downgrade it (and then upgrade it):
$ pkg_delete courier-imap\*
$ pkg_add -r courier-imap
$ portupgrade courier-imap
The last step gave me some trouble. It actually didn't install (it should - but I don't know why it didn't), so I had to go in and manually install it from the ports tree. I don't know what happened, but running portupgrade on all the installed ports caused some sort of problem.
Once the port was installed, I still wasn't able to get it to run. I tried looking for documentation, but I couldn't find any really. The problem had to do with the authdaemond daemon. It wasn't starting up. However, once I added courier_authdaemond_enable="YES" to /etc/rc.conf, it started working fine.
I don't know what it is with setting up MTA's - I've always had trouble setting mine up. They're the first things to break, and the last things to get fixed.