Adding cron jobs via cPanel
From SuperbHosting Support Wiki
If you are adding cron jobs via the cPanel interface, and they are not being saved, there is a problem with the permissions set on your crontab. To fix this issue, run the following command via an SSH session.
chmod a+s /usr/bin/crontab
This sets the permissions that allow cPanel/WHM to write to the cron tab properly.
