I'm using user@domain authentication with dovecot/postfix POP3/IMAP is working fine. When I try to use squirrelmail/roundcube mail I cannot authenticate. I get in the logs: Mar 16 13:26:45 weburl-l dovecot: auth(default): pam(_burla.org_alvaro,127.0.0.1): pam_authenticate() failed: User not known to the underlying authentication module The strange thing is that on a specific domain (the first I created) it's working with squirrel/roundcube too on all users I create. On other domains it's not working. Any hints on this?