Server responded: -ERR Login failed

I've installed the demo version and it worked fine, when I install atmailopen I get an error when logging in.  Does anyone have any ideas why one version works and the other one does not?

on the web login page I get:
Server responded: -ERR Login failed

and in my maillog I get:
Jan 28 12:23:18 siebrecht dovecot: imap-login: Disconnected: user=<removed@siebrecht.us>, method=PLAIN, rip=207.177.9.224, lip=207.177.9.224, secured

I'm using centos 5 and dovecot as my imap server.