If you have root access - can ftp the server or ssh and use vi or nano to edit.

'/var/cpanel/userdata/vybz/vybz.live.php-fpm.yaml'

is actually - /var/cpanel/userdata/replace_with_acct_name/your_domain.tld.php-fpm.yaml 

and add the following line - 

php_admin_value_disable_functions: { name: 'php_admin_value[disable_functions]', value: none }

at the bottom of the file.

Hope this helps

I also had to go back in to WHM (root), not cPanel. 

WHM > Software > MultiPHP Manager  - Look for "Edit function list" click the expand arrow ">" and remove the disable function that is likely there by default.

Thank you Jym. That was exactly the right answer!!