Okay. I hope you have got phpMyAdmin installed.(ore other database tool)
1. Open phpMyAdmin and go to the roundcube database and open the table "users", there should be no entrys, if not so truncate the table.
2. Log in with your "454684_alias" username and password in roundcube. Then log out.
(It's to save the login data in database, do it for each user that should access to roundcube)
3. Log in to your database with phpMyAdmin.
4. Go to the users table. 4. Set the field "alias" to
youralias@yourpage.com5. Ready! Open Roundcube and log in with
youralias@yourpage.com and your password! Then go to Options->Adresser and set it to
youralias@yourpage.comGood Luck, I hope it works!
PS: In the main.conf.php file set: (Line 32)
$rcmail_config['auto_create_user'] = FALSE;
(To prevent logins from other members of your mailserver)
If you have always problems i can send you my main.conf.php