I followed the tutorial http://www.howtoforge.com/virtual-users-domains-postfix-courier-mysql-squirrelmail-ubuntu-10.04 and everything went fine, except.... I have a problem with adding users and domains. I added firstname.lastname@example.org. ( form the tutorial ) and it works just fine, but if I add another domain or another email address, I cannot login. I restarted the postfix and the mysql and the courier-imap... but still the same problem. I am getting this error: ERROR: ERROR: Connection dropped by IMAP server. Can somebody help me?