> <other.mailserver.net #5.5.0 smtp;550
> Relaying not allowed>
I'm going to assume that the server's exteral IP address and that the DNS server are setup correctly.
It appears that your server doesn't recognize the primary domain on your server. We could probably dig into the db files and figure it out, but it might be faster to just reconfigure.
You might try changing the domain to a bogus one from the server console, reboot, then change the domain back to the correct one.
Hopefully that will fix the problem.
If not, you can always try:
/sbin/e-smith/signal-event post-upgrade
/sbin/e-smith/signal-event reboot
If that doesn't fix it, I'm out of easy ideas.
Steve