squirrelmail on ubuntu 12.04: cannot receiving mails
 

I've intalled squirrelmail on ubuntu server 12.04. Everything seems to look OK. But the user can not receive email, even localhost. I've been googling around, but so far it's still not working.

Does someone know where the problem can be?

You can check your log files for more detailed information on what may be wrong.

I've checked the log files (mail.log), no errors. And there is no other log files for dovecot & postfix