Roundcube databases are not generated when accessing Webmail

Symptoms

In some circumstances, you may find that Roundcube loads with the following error message:

DATABASE ERROR: CONNECTION FAILED!

Unable to connect to the database!
Please contact your server-administrator.

And the Roundcube databases in /home/$user/etc/$domain are not present.

Description

The issue is most often caused by the cPanel PHP-FPM process hanging onto connections. Sending PHP-FPM a hard restart generally addresses the problem.

Workaround

To restart the process, we recommend running these commands:

/scripts/restartsrv_cpanel_php_fpm --stop
/scripts/restartsrv_cpanel_php_fpm --start