No connection to server possible

I run the plex Server on a Win10 PC and use a xbox one as Client.
One week ago I had no issues.
Then I updated the Windows Server AND (automatically) the xbox one app.
Since then the app does not connect to the Server anymore no matter what I tried. (even manual IP did not help)

Am I doing something wrong or is this a General bug?

What does your server show for remote access:
Did you setup port forwarding in the first place?
Settings → Server → Remote Access

Thanks for your answer.
Why would I Need remote Access?
My issue is that I cannot connect the Client to the plex Server within the same Network.

The Server works fine with the Fire TV Plex App in the same Network.
So I guess the issue is the Xbox One app?

See this

Not sure how your FireTV is working but I don’t have any of those myself to test with…