I've just tried setting up a postfix/dovecot server for the first time, with accounts managed through a mysql table. (via tutorial at http://library.linode.com/email/postfix/dovecot-mysql-ubuntu-10.04-lucid)
If I log into the actual box, the mail server works. If I send mail to a user (from either the local or remote domain) then login to the box via SSH & type 'mail', the logged-in user's mail shows up.
However, when I try to access the mail via thunderbird, it says 'no messages'. It says the server details are fine, it accepts the password - but, well, no mail. Have tried in both IMAP & POP3.
Any ideas how to go about diagnosing this? I'm completely at a loss.