Wms layers disappear

Hi, I like to use the Norwegian raster statkart together with the official slope map as a Wms overlay (https://nve.geodataonline.no/arcgis/services/Bratthet/MapServer/WMSServer?request=GetCapabilities&service=Wms). I recently switched to the subscription model, and here, I cannot get the overlay to stick. When I restart the app, it vanishes, and when I click the wms-button on the map screen, I get an error 'can't read map configuration'. When I reinitialize everything works fine. Any ideas what might cause this? Best, Achim