I have configured a test farm for Hybrid OneDrive and Sites using the Hybrid Wizard picker. The App Launcher is working (although extremely slow to load) and profile redirection from search results is working correctly. Problem is users cannot follow on-premise sites and see them listed in the Following list online. What I'm not sure if this is due to the hybrid setup or due to the on-premise UPS, proxy configs or something else. Creating a local personal site and Content following was never enabled on-premise since we have ODfb sites but I have even tried granting that to all users. The UI error is InternalError : Could not follow the item https://somesite.com with these founds in ULS logs
Cannot find site lookup info for request Uri https://xxxx-my.sharepoint.com/.
FollowedContent.FollowItem:Exception:System.Net.WebException: Unable to connect to the remote server ---> System.Net.Sockets.SocketException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond