Невозможно отправить push-уведомление firebase в IOS с помощью java

Я отправляю push-уведомление firebase, используя Java для IOS. ниже мой код.

    public class SendNotifi {
    public final static String AUTH_KEY_FCM = "AIzaSyBgF...............";
    public final static String API_URL_FCM = "https://fcm.googleapis.com/fcm/send";
    // userDeviceIdKey is the device id you will query from your database     
    public static void pushFCMNotification(String userDeviceIdKey) throws     Exception{

    String authKey = AUTH_KEY_FCM;   // You FCM AUTH key
    String FMCurl = API_URL_FCM;     

    URL url = new URL(FMCurl);
    HttpURLConnection conn = (HttpURLConnection) url.openConnection();

    conn.setUseCaches(false);
    conn.setDoInput(true);
    conn.setDoOutput(true);

    conn.setRequestMethod("POST");
    conn.setRequestProperty("Authorization","key="+authKey);
    conn.setRequestProperty("Content-Type","application/json");

    JSONObject json = new JSONObject();
    json.put("to",userDeviceIdKey.trim());
    JSONObject info = new JSONObject();

    info.put("title", "Notificatoin Title - IOS");   // Notification title
    info.put("body", "Hello Test notification - IOS"); // Notification body
    info.put("badge", "1"); 
    json.put("notification", info);
    json.put("priority", "high");

    System.out.println("json : " +json);

    OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
    wr.write(json.toString());
    wr.flush();

    BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
    String inputLine;
    StringBuffer response = new StringBuffer();

    while ((inputLine = in.readLine()) != null) {
        response.append(inputLine);
    }
    in.close();

    System.out.println(response.toString());
    }
    public static void main(String main[])
    {
        try {
            SendNotifi.pushFCMNotification("e_0k8MPAXpI:APA91bFrz3MkWS0V9E_PJMGwtFppYhR6ap9rD53nB-Wxkosij1jDDuPDXRw__l4tzOOsGaEm_j02a20oJGLimKvTuZSqRs6aTcbizTMuYMp6_1jB4U7RCl2A_NdWEHIMlaAl6YN1o_Hv");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Это не работает нормально для IOS.

Я получил подтверждение успеха в ответ, но я не получил никаких push-уведомлений в IOS.

{"multicast_id":6591278961512996707,"success":1,"failure":0,"canonical_ids":0,"results":[{"message_id":"0:1474009869605736%2f4186c42f4186c4"}]}

Заранее спасибо.