无法使用Firebase在iOS中接收通知

我在测试中使用Firebase控制台在iOS中接收通知。起初它说我已连接到Firebase并收到消息ID，但随后出现了一个错误

警告：Application delegate收到了对-Application:DidReceiveEmotentification:fetchCompletionHandler:的调用，但从未调用过完成处理程序。

和

无法连接到FCM。Error Domain=com.google.fcm Code=2001“（空）”如何解决此问题

这是我的DidReceiveMotonification代码

// [START receive_message]
 - (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo
    fetchCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler {
// If you are receiving a notification message while your app is in the background,
// this callback will not be fired till the user taps on the notification launching the application.
// TODO: Handle data of notification

// Print message ID.
NSLog(@"Message ID: %@", userInfo[@"gcm.message_id"]);

// Pring full message.
NSLog(@"%@", userInfo);
}
// [END receive_message]

尝试添加：

completionHandler(UIBackgroundFetchResultNoData);

在你的DidReceiveMotonification方法结束时