In ArcGIS Experience Builder, adding a KML file through the Add Data widget returns the error "The file <name> cannot be successfully uploaded."

Workaround

Create a custom widget by copying the folder add-data located at <EBDevInstallFolder>\client\dist\widgets\common file path and changing the line below in the file widget.js located at <CustomWidgetFolder>\dist\runtime file path:

From:

return`${null===(o=(0,e.getAppStore)().getState())||void 0===o?void 0:o.portalUrl}sharing/kml`

To:

 return`${null===(o=(0,e.getAppStore)().getState())||void 0===o?void 0:o.portalUrl}/sharing/kml`

Steps to Reproduce