If you are getting a 404 not found error while accessing Roundcube, please do the following.
1. Remove the current Roundcube configuration file.
rm -f /usr/local/cpanel/base/3rdparty/roundcube/config/main.inc.php
2. Force update the Roundcube.
/usr/local/cpanel/bin/update-roundcube --force
This should fix the issue.
