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Select WMTS at "Choose GIS-server"
The WMTS server URL generally ends with 'WMTS'.
When layers with a EPSG:3857 projection are available these will be listed. These can be selected and added to the map.
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https://server.arcgisonline.com/arcgis/rest/services/World_Imagery/MapServer/WMTS/
Arcrest
Select Arcrest at "Choose GIS-server"
The Arcrest server URL contains a string like 'arcgis' or 'arcrest'. The URL that needs to be added generally ends with 'MapServer'.
When layers with a EPSG:3857 projection are available these will be listed. These can be selected and added to the map.
For example:
https://services.arcgisonline.com/arcgis/rest/services/World_Imagery/MapServer/