Undefined curl_init() Function ErrorsTroubleshoot and resolve Call to undefined function curl_init() errors.
Undefined Method Importing ErrorsTroubleshoot and resolve Call to undefined method getRawHeader() errors.
Undefined PHPMailer Function ErrorsTroubleshoot and resolve Call to undefined function PHPMailer HPMailerscapeshellarg() errors.
Unexpected Next Due DateTroubleshoot and resolve unexpected changes to a service's Next Due Date value.
Unexpected Service SuspensionsThe system is unexpectedly suspending services (for example, hosting accounts).
Unexpected Service TerminationsThe system is unexpectedly terminating services (for example, hosting accounts).
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.
Update Channel ErrorsTroubleshoot and resolve Make certain that you have selected a valid Update Channel and then try again errors.
Update Dry Run ErrorsTroubleshoot and resolve Apply update dry-run detected permission issues errors.
User Redirected to Wrong PageTroubleshoot and resolve issues that redirect users to an incorrect page.