notifications are not received despite 200 response code about laravel-firebase HOT 3 CLOSED

 $title = 'My Notification Title';
				$body = 'My Notification Body';
			//	$imageUrl = 'http://lorempixel.com/400/200/';

				$notification = Notification::fromArray([
					'title' => $title,
					'body' => $body,
				//	'image' => $imageUrl,
				]);

				$notification = Notification::create($title, $body);

				$changedNotification = $notification
					->withTitle('Changed title')
					->withBody('Changed body');
				//	->withImageUrl('http://lorempixel.com/200/400/');
					
					//return $notification;
					
					$topic = 'a-topic';

				$message = CloudMessage::withTarget('topic', $topic)
				->withNotification($notification) // optional
							//->withData($data) // optional
						;
                               $messaging->send($message);