We have a little known web based email client installed at http://webmail.mapserverpro.com/
login with user@yourdomain.tld - you must login with a normal account, aliases are not supported for logins.
All clients are welcome to use this link. Features incude support for almost all languages, folder and contacts management. Settings are stored in a database, not browser cookies. So your preferences will not change when accesing from multiple locations.
Best Regards,
MapserverPro Team