cPanel webmail woes
If you’re having issues with any webmail application that is included with cPanel have no fear! Just run the following command from ssh or a command line terminal as root or escalated user:
For Roundcube
/usr/local/cpanel/bin/update-roundcube --force
For Horde
/usr/local/cpanel/bin/update-horde --force
For SquirrelMail
/usr/local/cpanel/bin/update-squirrelmail --force
that will fix most issues, including with the databases themselves.