Multiplayer: Name server authentification failed - invalid application id

I’m new to Felgo and am trying to get acquaintance to the concepts of multiplayer game with a very simple example:

The example I made (copied) is only to register to the FelgoGameNetwork and select one player to play with. The Main.qml has only a few code lines (s. code)

import Felgo 3.0
import QtQuick 2.0

GameWindow {
    id: gameWindow

    FelgoGameNetwork {
        id: gameNetwork
        // created in the Felgo Web Dashboard
        gameId: 903
        secret: "3f8ec993-329a-4f7e-949f-e71eca1a1bbd"
        multiplayerItem: myMultiplayer
      }

      FelgoMultiplayer {
        id: myMultiplayer
        appKey: "063B31DE67EA5E8.."
        gameNetworkItem: gameNetwork
        multiplayerView: myMultiplayerView
        playerCount: 2
      }

    activeScene: scene

    screenWidth: 960
    screenHeight: 640

    Scene {
        id: scene

        width: 480
        height: 320

        SimpleButton {
           text: "Start Game"
           anchors.centerIn: parent
           onClicked: myMultiplayer.showMatchmaking()
        }

        MultiplayerView{
           id: myMultiplayerView
           visible: false
           onShowCalled: myMultiplayerView.visible = true
           onBackClicked: myMultiplayerView.visible = false
        }

    }
}

I defined an app and generate the app key. This can be compiled without any error. But if I click on “Start Game”, and click “create a game”, it shows “connecting..” and seems never to get connected. In the console I see this error:

NameServer: Connected

: State: ConnectingToNameServer -> ConnectedToNameServer

NameServer: Authenticate…; State: ConnectedServer -> :

Error: 3101 NameServer authentication failed: 32767 Invalid application id

It seems to me that the FelgoGameNetwork can not find my game defined in my profile. But I’ve given my gameid, appkey in .pro-File, config.json according to the documentation?!

Thank you in advance for any help.

Gang