Problems with Courier IMAP connecting to virtual users
 

I recently set up my first mail server. I used this guide:

http://flurdy.com/docs/postfix/

The server I set up was pretty bare bones, nothing more than the Postfix server, MySQL, Courier IMAP. It didn't have virus protection or anything. I also set up a few accounts. The virtual users mailboxes were stored in /var/spool/mail/virtual. I used telnet to e-mail myself at gene@mail.hea.org account and it created a directory for gene@mail.hea.org and the directory underneath was cur, new, tmp with a new message in new. However, when I tried to use thunderbird to connect to the account I was given a login to mail.hea.org failed error. Now the strange part to me was that I was able to get 2 accounts to work yesterday. I don't know what happened since I couldn't get in earlier with the same accounts and I didn't remember changing anything. I did notice however that in the user profile accounts I had (I believe) 2 new Courier files. I don't recall the names (I since deleted them). So even though some accounts wouldn't work some would and I couldn't think of what I did that could make a difference. Is there something I need to do with Courier IMAP to instantiate the accounts or something? Any ideas of what might be causing this?