Install and Enable Ioncube Loader WHM
this PHP extension does not come preinstalled on cPanel
WHMCS require the use of ionCube Loader to encode secured PHP files. IonCube Loader is an extension for PHP that does not come preinstalled on cPanel. It needs to be installed and enabled.
1. Log into the WHM as the user root.
2. Go to Software - EasyApache (Apache Update)
Information Delivery Specialist