I have a client with SBS2003 using Exchange. Their individual POP3 accounts at the ISP are picked-up by Exchange and distributed internally. Because they have no static IP, we are sending mail to the ISP's smart host rather than delivering directly. Recently the are getting *some* not all of their messages returned with the following message:
"Relaying denied: You must check for new mail before sending mail."
How do I force Exchange to retrieve mail on an account before trying to send?
Can it check only one of the valid accounts yet forward mail from any internal user?
Perhaps unrelated - can I have Exchange check for new mail more often than every 15 minutes (and might this solve the problem)?