UBB.threads PHP Forum Software Community Forums UBB.classic UBB.classic 6 Support Exchange 2003 E-mail Problems

I am getting errors from my board when it tries to send an E-mail:

An error has occurred:

Unable to connect to the SMTP server. The following error was returned: Unknown error

The server either does not exist, or rejected the connection.

Please ensure that the UBB is allowed to relay mail through the server.

I am running Windows 2003 and Exchange 2003. I have played around with a bunch of relay settings in Exchange but can't seem to get this thing to send mail. Any Exchagne 2003 Gurus out there know what I am missing?