When you import external layers into your map using WMS and do not see the layers on your map, there can be at least two reasons:
Each WMS provides a limited number of available CRS. If the selected WMS does not support EPSG 3857, we can currently not display it on the map. Please reach out if you encounter this issue.
The external WMS might have an issue. We encountered various WMS stated that they support EPSG 3857 but turned out to have bugs. If you encounter this issue, please reach out to the provider of the WMS.
