Cron Jobs

Hello Everyone,
I am really struggling to get a successful php cron setup

Environment

Ubuntu Linux 18.04.2
Webmin version 1.900
Usermin version 1.751
Virtualmin version 6.06-2

When running to following commands i get the following errors

/usr/bin/php /home/username/public_html/billing/crons/cron.php

Site error: the ionCube PHP Loader needs to be installed. This is a widely used PHP extension for running ionCube protected PHP code, website security and malware blocking.

Please visit get-loader.ioncube.com for install assistance.

/usr/bin/wget https://mydomain/billing/crons/cron.php

This says it works but it does not execute so confused by this as well

What is the actual command to execute a php cron please?

Thanks

Rockyuk