Unable to Communicate ErrorsTroubleshoot and resolve Unable to communicate with the WHMCS installation errors.
Unable to Display Pricing ErrorsTroubleshoot and resolve an Unable to display TLD cost pricing error.
Unexpected PayPal Cancellation EmailsTroubleshoot and resolve issues with customers receiving unexpected subscription cancellation emails from PayPal®.
Unregistered Address ErrorsTroubleshoot and resolve The sender's email address is not registered. (WHMCS 8.4 and later) or Unregistered Email Address (WHMCS 8.3 and earlier) errors.