VertiGIS Printing Experience Builder Enterprise Manifest URL seems to lead nowhere

Hello,

I recently tried to configure an Experience Builder widget within an Enterprise Portal, and the manifest URL seems to not work. The manifest URL was created by following the VertiGIS Studio Printing Experience Builder set up documentation for Enterprise. The Enterprise version that we are running is 11.1

I configured the base manifest URL from the link above for the version of what I believe to be the correct Experience Builder Widget Release Version for our Enterprise version: 2.1.0 

Manifest URL: https://static.vertigis.com/exb-widgets/printing/2.1.0/manifest.json 

In the below image, the error of: The URL does not reference an AppBuilder Extension appears. 

Please advise as to the proper process or if changes have been made and the documentation is now outdated. 

Thanks, 

Cole