qgis - Getting more details by zooming in web-client?

today I've setup a qgis server and web client on my windows machine. Here is my WebClient.

Now I'd like to test out everything. I tried to zoom in to the map, but it just stops by 1:2257 . I need more details.

I've checked the Settings in the GlobalOptions.js

    var MapOptions = {
  projection: new OpenLayers.Projection(authid),
  units: "m",
//  maxScale:50,
//  minScale:4000000,
  numZoomLevels:ZOOM_LEVELS,
  fractionalZoom: !enableWmtsBaseLayers && !enableBGMaps,
  transitionEffect:"resize",
  controls: []

I've tried to uncomment the max-/minscale and changed the values, but nothing works.

I hope you can help me to configure my new QGIS web-client.

(for example, I want to let the user zoom from 1:40000 to 1:50 like here.)