The URL that is passed to the SharePoint connector must not include the AllItems.aspx suffix. Additionally, only the ‘site’ URL of a SharePoint site can be passed, for example:
The above is incorrect because it points directly to a list. To access this list, the bolded section of the URL needs to be removed and then the list will become available for selection in the dialog box below. When the extension is pointed to the SubSite, lists immediately below are available for consumption.
In the figure above, circles are used to represent lists and squares are used to represent SharePoint sites. Use the following as an example:
For lists 1 and 2, use: https://example-sharepoint.net/sites/TopSite/
For lists 3 and 4, use: https://example-sharepoint.net/sites/TopSite/SubSite/