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.
Whoops Exception ErrorsTroubleshoot and resolve Whoops Exception Maximum execution time of 30 seconds exceeded errors.