When a mailbox user logs in (i.e., login with firstname.lastname@example.org and the password) they have a Mail and Mailing lists tab at the top of the control panel. If you click on the Mailing list tab, it comes back: ERROR Permission denied. 0: /usr/local/psa/admin/htdocs/domains/maillists/maillists.php:2 psaerror(string "Permission denied.") I can click that tab okay when I log in either as the server admin or as the domain user. It's only when logging in as the mail user that the error message is displayed.