Webmail login error

I'm having a problem with webmail on Server 10.3.4, and I've tried every solution I've found on the web, to no avail. When I attempt to log in to Webmail, I get the error message: ERROR Unknown user or password incorrect. Go to the login page I've been through the squirrelmail config file and everything meshes with the server settings (i.e. domain name, login type, etc.). I'm using "Login" on the server and "Login" in squirrelmail. Webmail is enabled and IMAP is enabled for the server and for all users. The Web logs for my attempts at logging into webmail are as follows: "GET /webmail HTTP/1.1" 302 5 "GET /webmail/src/login.php HTTP/1.1" 200 2088 "POST /webmail/src/redirect.php HTTP/1.1" 200 1074 The IMAP logs show nothing for these login attempts. The only way I can get anything to show up in the IMAP logs is to log into cyradm within the Terminal. I've tried messing with php.ini, imapd.conf, cyrus.conf, cyradm, etc. and haven't found anything that works. Apple tech support suggested that we might need to "modify cyrus files." Not sure which files or modifications that refers to. Anyone ever dealt with this or have any suggestions/need more info?