Symfony\Component\Debug\Exception\FlattenException::getMessage PHP Method

    public function getMessage()
    {
        return $this->message;
    }

 public function showAction(Request $request, FlattenException $exception, DebugLoggerInterface $logger = null)
 {
     if ($exception->getClass() == MailException::class) {
         return new Response($this->twig->render('CantigaCoreBundle:Exception:mail-exception.html.twig', array('message' => $exception->getMessage())), 501);
     }
     return parent::showAction($request, $exception, $logger);
 }