Error when adding WMS background layer 'Error: Check your url and version and try again '

[beunderf]

Hello all,

I want to add these beautiful Arcgis WMS layers to my map visual in Qlik Saas, but I keep ending up with an error

URL: https://geo.rijkswaterstaat.nl/arcgis/rest/services/GDR/actuele_wegenlijst/MapServer

I added 'geo.rijkswaterstaat.nl' to my 'Content Security Policy' list:

Next I want to add a WMS Background Layer into my app, by using the following WMS server URL in my layer:
https://geo.rijkswaterstaat.nl/arcgis/rest/services/GDR/actuele_wegenlijst/MapServer

When I click on 'Load WMS' the following error keeps showing up. What am I doing wrong? 

Please help 🙂

Frank