SMTP Connections. Failed. Asking for PW

Friends, I have been using cPanel since the dawn of time. But this my first attempt to running my own cPanel installation, and so far, so good. Topology consists of a couple of load-balanced, DSL connections. But I'm having some strageness occur here, I'm finding that I'm being prompted, for a new password for an email accounts, frequently. Another issue I seem to be having is some of the SMTP-connection issue, which seems to be intermittent, ? Any suggestions?