If you are getting the error with Horde webmail such as follows
"User [email protected] is not authorised for Mail"
Solution :
1. Backup horde database
# cd /var/lib/mysql
# mysqldump horde > horde.sql
2. Drop horde database
# mysqladmin drop horde
3. Update horde package using command.
# /usr/local/cpanel/bin/update-horde --force
4. Now check and repair the horde database.
# mysqlcheck -r -o horde