On the mail.log, i found that when i try to telnet the server via POP or IMAP i have:
Feb 15 16:49:32 server1 imapd: chdir test.loc/la/: No such file or directory
Feb 15 16:49:48 server1 pop3d: Connection, ip=[::ffff:192.168.0.100]
Feb 15 16:50:03 server1 pop3d: chdir test.loc/la/: No such file or directory
'test.loc' is the domain name, and 'la' is a user that i try to setup mail for : ''firstname.lastname@example.org"
thanks for your help.