I am new to ArcGIS. When I am trying to add a map to Story Maps, I am unable to pick my created basemap when I try to add an Express Basemap (I just want a map without border lines between countries, withouth labels,...) I created one using ArcGIS Pro and I get the below error:
The map you selected cannot be used here. Please choose a different web map.
This is the link to the map: https://arcg.is/1GfuCL0I had this same issue when I was new to ArcGIS, and it usually happens because Story Maps doesn’t support some basemap settings coming straight from ArcGIS Pro. I had to republish mine through the Map Viewer with compatible layers before Story Maps accepted it. Once I did that, the error disappeared instantly kind of like how APK works smoothly once you set it up right. Try that method, it solved the same problem for me.
Can you try and create a web map within Map Viewer and see if that works within Storymaps?