我能够在Android中使用FCM生成令牌，但是当我发送消息时它会失败

Question

我已生成令牌但仍无法收到通知。 当我将消息发送到用户段时，它显示状态已完成但我没有收到任何通知。 我正在上传我的清单文件。

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.sumit.v_care">
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
    <uses-permission android:name="android.permission.VIBRATE"/>
    <uses-permission android:name="com.google.android.c2dm.permission.RECIEVE"/>
    <uses-permission android:name="android.permission.WAKE_LOCK"/>
    <uses-permission android:name="com.google.android.c2dm.permission.message"/>
    <application
        android:allowBackup="true"
        android:icon="@mipmap/vcare"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".memberlog"
            android:parentActivityName=".MainActivity">

        </activity>
        <activity android:name=".memberp"
            android:parentActivityName=".memberlog">

        </activity>
        <activity android:name=".donate"
            android:parentActivityName=".memberp">

        </activity>
        <activity android:name=".ResultActivity">
            </activity>
        <service
            android:name=".Mymessagingservice"
            android:enabled="true"
            android:exported="true">
            <intent-filter>

                <action android:name="com.google.firebase.MESSAGING_EVENT"/>
            </intent-filter>
        </service>

        <service
            android:name=".MyFirebaseInstanceIDService">
            <intent-filter>
                <action android:name="com.google.firebase.INSTANCE_ID_EVENT"/>
            </intent-filter>
        </service>
    </application>

</manifest>

Mymessagingservice.java

package com.example.sumit.v_care;

import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.media.RingtoneManager;
import android.net.Uri;
import android.support.v4.app.NotificationCompat;
import android.util.Log;

import com.google.firebase.messaging.FirebaseMessagingService;
import com.google.firebase.messaging.RemoteMessage;

/**
 * Created by Sumit on 22-02-2017.
 */

public class Mymessagingservice extends FirebaseMessagingService {
    private static final String TAG = "MyFirebaseMsgService";

    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        //Displaying data in log
        //It is optional
        Log.d(TAG, "From: " + remoteMessage.getFrom());
        Log.d(TAG, "Notification Message Body: " + remoteMessage.getNotification().getBody());

        //Calling method to generate notification
        sendNotification(remoteMessage.getNotification().getBody());
    }

    //This method is only generating push notification
    //It is same as we did in earlier posts
    private void sendNotification(String messageBody) {
        Intent intent = new Intent(this, MainActivity.class);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent,
                PendingIntent.FLAG_ONE_SHOT);

        Uri defaultSoundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
        NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this)
                .setSmallIcon(R.mipmap.ic_launcher)
                .setContentTitle("Firebase Push Notification")
                .setContentText(messageBody)
                .setAutoCancel(true)
                .setSound(defaultSoundUri)
                .setContentIntent(pendingIntent);

        NotificationManager notificationManager =
                (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

        notificationManager.notify(0, notificationBuilder.build());
    }
}