If you got following error message when accessing webmail using Squirrelmail or other brand:
Query: SELECT “INBOX”
Reason Given: Internal error occurred. Refer to server log for more information. [2009-11-03 15:47:40]
The cure is really easy. Check /home/user/mail/ and see its subdirectories’ permission.
In my case, I just need to perform chown command to assign the directories/files under user’s ownership and the problem is gone.