You will receive an error when accessing Horde, RoundCube or SquirrelMail from webmail on a cPanel installed server.
It allows you to login. But, when you access specific email account, it shows this message/error.
' Error User mail@Domain.com is not authorized for Mail (Host: *.*.*.*)."
It usually happens when cpanel update has issue OR you migrate the account or server OR rebuild it.
Run force cpanel update :
If problem persists then Horde database might be corrupt OR it needs a reset.
Check HORDE database if its corrupt then repair it. Command to check Horde database is
It will show the table which is corrupted. Replace horde_TableName.MYI with corrupted horde table name.
myisamchk -r -o /var/lib/mysql/horde/horde_TableName.MYI
Check webmail is working or not. If you still get the same message, then it’s time to completly reset horde database.
Take Horde database backup
mysqldump horde > horde.sql
Reset Horde with command below.