Troubleshoot and resolve Authentication failed errors while working with payment gateways.
Troubleshoot and resolve `<field> is required` errors while using Authorize.net.
Modules in WHMCS use templates to define what users see. You can customize these module templates using WHMCS's overrides system.
Troubleshoot and resolve issues with DUPLICATE_INVOICE_ID errors.
Troubleshoot and resolve issues with field is required errors in Authorize.net.
Troubleshoot and resolve issues with eWay credit card fields not displaying at checkout.
Troubleshoot and resolve processing issues that did not result in a log entry.