title: Firebase response says success, but no notification on device
body: <p>I used the following code to send a push notification from my server to an Android device:</p>
  
  <pre><code>public string SendNotification(string deviceId, string message)
  {
      string GoogleAppID = "anonymized";
      var SENDER_ID = "anonymized";
      var value = message;
      WebRequest tRequest;
      tRequest = WebRequest.Create("https://fcm.googleapis.com/fcm/send");
      tRequest.Method = "post";
      tRequest.ContentType = " application/x-www-form-urlencoded;charset=UTF-8";
      tRequest.Headers.Add(string.Format("Authorization: key={0}", GoogleAppID));
  
      tRequest.Headers.Add(string.Format("Sender: id={0}", SENDER_ID));
  
      string postData = "collapse_key=score_update&amp;time_to_live=108&amp;delay_while_idle=1&amp;data.message=" + value + "&amp;data.time=" + System.DateTime.Now.ToString() + "&amp;registration_id=" + deviceId + "";
      Console.WriteLine(postData);
      Byte[] byteArray = Encoding.UTF8.GetBytes(postData);
      tRequest.ContentLength = byteArray.Length;
  
      Stream dataStream = tRequest.GetRequestStream();
      dataStream.Write(byteArray, 0, byteArray.Length);
      dataStream.Close();
  
      WebResponse tResponse = tRequest.GetResponse();
  
      dataStream = tResponse.GetResponseStream();
  
      StreamReader tReader = new StreamReader(dataStream);
  
      String sResponseFromServer = tReader.ReadToEnd();
  
  
      tReader.Close();
      dataStream.Close();
      tResponse.Close();
      return sResponseFromServer;
  }  
  </code></pre>
  
  <p>I called the function like that:</p>
  
  <pre><code>string str = new AndroidGCMPushNotification().SendNotification(registration.DeviceToken, "Hello!");
  Console.WriteLine(str);
  </code></pre>
  
  <p>The feedback of firebase is the following:</p>
  
  <pre><code>id=0:1491212883976938%e6b70caa66d6cf16
  </code></pre>
  
  <p>The 0 says, the push notification was created successfully. But I don't receive the message on my Android device. I can exclude a networking problem.</p>
  
  <p>On my client side, I created this class:</p>
  
  <pre><code>[Service]
  [IntentFilter(new[] { "com.google.firebase.MESSAGING_EVENT" })]
  public class MyFirebaseMessagingService : FirebaseMessagingService
  {
      const string TAG = "MyFirebaseMsgService";
      public override void OnMessageReceived(RemoteMessage message)
      {
          Log.Debug(TAG, "From: " + message.From);
          Log.Debug(TAG, "Notification Message Body: " + message.GetNotification().Body);
      }
  }
  </code></pre>
  
  <p>Plus, I added the AndroidManifest.xml with the following:</p>
  
  <pre><code>&lt;service
      android:name=".MyFirebaseMessagingService"&gt;
    &lt;intent-filter&gt;
      &lt;action android:name="com.google.firebase.MESSAGING_EVENT"/&gt;
    &lt;/intent-filter&gt;
  &lt;/service&gt;
  </code></pre>
  
  <p>What could be my problem?</p>