我将通知发送到具有fcm的设备，但我无法收到通知

Question

我想向其他设备发送通知。我向FCM服务器使用了HTTP发布请求，其方法类型为：POST，URL：https://fcm.googleapis.com/fcm/send。当我与邮递员进行测试时，我在我的邮件中收到了通知设备，但是当我实施翻新的FCM服务时，我收到200响应，但收到任何通知。有人可以帮我吗？

//My ApiService
    @Headers("Authorization:key=******")
        @POST("https://fcm.googleapis.com/fcm/send")
        fun sendNotification(@Body body:NotificationRequest):Call<ResponseBody>





 val fm=FirebaseMessaging.getInstance()
            var token=FirebaseInstanceId.getInstance().token
            val datanoty=DataContent("my_custom_value",true)
            val noty=NotificationContent("title","body text","ic_notification")
            val notificationRequest=NotificationRequest(token!!,datanoty,noty)
           // tt.sendRegistrationToServer(FirebaseInstanceId.getInstance().token)
            RetrofitClient.instance.sendNotification(
                    notificationRequest)
                    .enqueue(object : Callback<ResponseBody> {
                override fun onResponse(call: Call<ResponseBody>, response: Response<ResponseBody>) {
                    if( response.code()==200)
                   Toast.makeText(context,"sendedYes",Toast.LENGTH_SHORT).show()
                    else if(response.code()==400)
                    Toast.makeText(context,"sendedNo",Toast.LENGTH_SHORT).show()
                    response.body()
                }

                override fun onFailure(call: Call<ResponseBody>, t: Throwable) {

                }




    //My notification Request
    class NotificationRequest(

            var to:String,
            data:DataContent,
            notification:NotificationContent ):Serializable

    class DataContent(my_custom_key:String,my_custom_key2:Boolean):Serializable
    class NotificationContent(title:String,body:String,icon:String):Serializable





    //myFirebaseMessagingService
     override fun onMessageReceived(remoteMessage: RemoteMessage?) {

            if (remoteMessage?.notification != null) {
                showNotification(remoteMessage.notification?.title, remoteMessage.notification?.body)
            }



            super.onMessageReceived(remoteMessage)

        }
        private fun showNotification(title: String?, body: String?) {
            val channelId=""
            val notificationId=101
            val manager =  this?.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
            createNotificationChannel(manager);
    //        val intent=FragmentTransactionUtilities.pushFragment(fragmentManager as FragmentManager,BlankFragment2.newInstance("",""))
            val intent= Intent(this, MapsActivity::class.java)
            val pendingIntent= PendingIntent.getActivity(this,0,intent, PendingIntent.FLAG_UPDATE_CURRENT)
            val soundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION)
            var builder = this?.let {
                NotificationCompat.Builder(it,"default_channel")
                        //.setSmallIcon(R.drawable.notification_icon)

                        .setContentText("")
                        .setSmallIcon(com.example.rahma.alerteaccidentapp.R.drawable.navigation_empty_icon)
                        .setContentTitle("New Accident Added")
                        //.setStyle(Notification.BigTextStyle().bigText("Much longer text that cannot fit one line..."))
                        .setStyle(NotificationCompat.BigTextStyle()
                                .bigText("Much longer text that cannot fit one line..."))
                        .setPriority(NotificationCompat.PRIORITY_DEFAULT)
                        .setContentIntent(pendingIntent)
                        .setAutoCancel(true)//close auto noty after click
                        .setSound(soundUri)
                        .build()
            }

            if (builder != null) {
                with(this?.let { NotificationManagerCompat.from(it) }) {
                    // notificationId is a unique int for each notification that you must define
                    manager?.notify(1, builder)
                }
            }
        }

        private fun createNotificationChannel(notificationManager: NotificationManager) {
            NotificationChannel.DEFAULT_CHANNEL_ID
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                //Create channel only if it is not already created
                if (notificationManager.getNotificationChannel(DEFAULT_CHANNEL_ID) == null) {
                    notificationManager.createNotificationChannel( NotificationChannel(
                            DEFAULT_CHANNEL_ID, DEFAULT_CHANNEL_NAME, NotificationManager.IMPORTANCE_DEFAULT
                    ));
                }
            }
        }

        override fun onNewToken(token: String?) {
            super.onNewToken(token)
            Toast.makeText(this, "Refreshed token: " + token,Toast.LENGTH_SHORT).show()
            sendRegistrationToServer(token)


}