I am trying to add our WMS-basemap into the Web AppBuilder BasemapGallery widget, but it fails, showing only red exclamation mark (no explanation).
I assume it is possible to add WMS service as a basemap there? I tried WMS with our national SRS (http://kaart.maaamet.ee/wms/alus?) and also EPSG:4326 (http://kaart.maaamet.ee/wms/alus-geo?) but both failed to load...
Is there any evident reason?
Estonian Land Board