Problem solved. Here's the issue. Netscape is saving the cert. If you
have reinstalled courier or the OS on the machine on which the cert was
generated, the authentication will fail, but the cert doesn't match the
cached one. Try removing the cert from netscape's settings (Under
Communicator->Tools->Security Info). After removing that cert and
re-authorizing it, all works perfectly. I found this out because we
were actually having the same issue with same-named certs with the web
server and SSL.