Troubleshooting an Undefined class constant 'Active' Oops Error Message upon ordering
After applying the 7.9.0 update and placing an order, the following Oops error is displayed when the Only Auto Provision for Existing option is enabled.
exception 'Whoops\Exception\ErrorException' with message 'Undefined class constant 'Active'' in /home/v79whmcssupport/public_html/whmcs/includes/invoicefunctions.php:0
Disable the Setup > General Settings > Ordering tab > Only Auto Provision for Existing option
Please apply the 7.9.1 Maintenance Release via the Utilities > Update WHMCS page.
A hotfix has been created for 7.9.0 only which will resolve the cause of this error: