Payment Processing Issues

From WHMCS Documentation

Use the instructions below to resolve common payment processing issues:

Merchant Gateway Declining or Failing

Check Billing > Gateway Log for your payment gateway's returned response. This should indicate the problem. Then, look up the error codes in your payment gateway's documentation or contact their support team.

For more information on common errors, see each payment gateway's dedicated documentation.

Blank Payment Gateway Page

Usually, this indicates a double copy of a gateway file in the modules/gateway directory, either in the .htaccess/php.ini file or another non-WHMCS file in the directory. Removing this should resolve your problem.

Gateway Module Error: Configuration Function (_config) not found

In WHMCS 7.8 and higher, Configuration () > System Settings > Payment Gateways (Setup > Payments > Payment Gateways in WHMCS 7.8 through 7.10) will check whether the gateways in the /modules/gateways folder contain the *_config function, which is required for use with WHMCS.

  • If any gateways are missing this function, a message will display at the top of the page with a list of applicable gateway files. Audit each of them and remove or correct them to resolve this.
  • To correct them, add the function to the file according to our documentation.
  • If you are using a third-party gateway, you may need to contact them to update the gateway module.

This may also indicate unexpected non-gateway files in the /modules/gateways folder. If this is the cause, audit and remove the unneeded files.

User Redirected to Wrong Page on Checkout

If you have customised your WHMCS header template and added or removed a form, you must update the forwardpage.tpl template file.

By default, this submits form 0 or 1 on the page. If you add a form to your header, increment the forms[x] setting.

Invalid Access Attempt

To avoid this error, make sure that you are logging in to the Admin Area using the exact URL in Configuration () > System Settings > General Settings, or, prior to WHMCS 8.0, Setup > General Settings.

For example, if the WHMCS System URL is http://www.example.com/whmcs/, you would need to log in to your Admin Area at http://www.example.com/whmcs/admin. If you log in at http://example.com/whmcs/admin, omitting the www., you will see the Invalid Access Attempt message.