public function render($request, Throwable $exception)
 {
 if ($exception instanceof \Illuminate\Http\Exceptions\PostTooLargeException) {
     return $this->showCustomErrorPage();
 }
     return parent::render($request, $exception);
 }

 protected function showCustomErrorPage()
 {
     return \Illuminate\Support\Facades\Redirect::back()->withErrors(['max_upload' => 'The Message']);
 }