I'd like to add a SharePoint Hosted Add-In from the AppCatalog to a SharePoint 2016 on-premises Website, but in the Site Contents of that Website the SharePoint Hosted Add-In is stuck being grey with the message "We're adding your app".
I have the SharePoint Environment Configured as described in SharePoint 2016 : A Deep Dive into SharePoint Add-in Environment Configuration and SharePoint Hosted Add-in Creation and Upgrade, I have checked the windows services and both
SharePoint Administration and
SharePoint Timer Service are running.
So, how can I get the SharePoint Add-In to be successfully added to the SharePoint Website?