In ArcGIS Field Maps, data of a WMS service in a web map is not displayable when opening the map in the ArcGIS Field Maps mobile app.

Solución alternativa

In ArcGIS Pro: 

• Open any map of Switzerland with LV95 from Living Atlas in ArcGIS Pro.
• Convert map to basemap and insert into new map as basemap. refer to the following documentation https://pro.arcgis.com/en/pro-app/latest/help/mapping/map-authoring/author-a-basemap.htm for more information.
• Insert the WMS: https://cavigelli.mapplus.ch/cgi-bin/mapserv?map=/data/Client_Data/cavigelli/laax/wms_lk_abwasser_sia405.map&REQUEST=GetCapabilities&SERVICE=WMS [cavigelli.mapplus.ch]&
• Zoom to Laax.
• Publish the map as web map and open the Map in ArcGIS Field Maps.

Pasos para reproducir