Yes, trough the mailsuer login: https://www.yourdomain.com:81/mailuser/ (Do not replace the word mailuser with the username).
Another question . If I install Squirrelmail, does it be available in the user login area? Can user access it from is login?
All webmail packages for ISPConfig are not part of the mailuser login area, they are separate but can be accessed with the email username and password of course. The mailuser login is only for changing the password or enabling a autoresponder.
