After applying the 7.8 update and placing an order via cart.php, the following Oops! error is displayed:

Error: Module Not Found

Navigating to the Setup > Payments > Payment Gateways page in the WHMCS admin area, will show an error:

The Payment Solution module could not be loaded, most likely because it has been removed. You should deactivate it now.

A payment gateway record is activated and configured, but the corresponding file is missing from the /modules/gateways directory.

There are two possible solutions:

1. Restore the missing module file to the /modules/gateways directory. You may need to upload the file to your server via SFTP or restore from a backup.

2. Deactivate the missing module, switching customers to a different payment gateway module in the process. Instructions for doing this are located in our documentation.