PR4100 Plex access OK but can't connect to server with Finder or Safari

I recently purchased a PR4100 to use as a media server for my home MAC network. Everything has been working fine until this week. I can still access my content via the Plex App for Apple TV and Amazon Firestick. However, I am no longer able to access the servers Dashboard nor connect to it via a Finder window. Anyone with ideas? Thanks, Bob

Maybe same as this problem?