Comment 2 for bug 890756

This just recently became an issue after upgrading from 11.10 to 12.04. syslog indicated that authentication succeeded, but courier then apparently dropped the connection after authentication (diagnosed via telnet). The solution proposed by ginoputrino solved the issue:

apt-get install fam
apt-get install courier-imap courier-imap-ssl

(see http://ubuntuforums.org/showpost.php?s=7460080f58fa5ea3c972281a710baea0&p=11874468&postcount=10 )