Sascha Van Gerwen
This plugin is NOT compatible with WHMCS v7.2.1 if you are using PHP 7.0. The IonCube loader for this plugin is compiled for PHP 5.4, doesn't work with PHP 7.0 or higher.
Could send us a email to email@example.com so that we can check what is going wrong. Or in this case send you our latest BETA module.