Suddenly unable to connect to offline LAN PC by IP address

I've been using TV for a long time with great success.  In my case, I use TV out in the field where there is no internet connection.  I have a miniPC (Intel NUC) that broadcasts it's own local area network.  Then I connect my laptop or phone to the NUC LAN.  At that point I use TV to log in to the NUC via it's IP address to remotely control the NUC.

However, recently this has stopped working. No matter what I do I cannot connect to the NUC remotely.  TV is set up the same it has always been, but it just won't connect anymore.  Again, this is if I do not have internet access.  At home when all devices are connected to the internet TV works fine.  I've check firewall setting to make sure TV is an allowed app.

I will also mention that I tried another remote desktop application with the same results.  If there is no internet connection I cannot log in to the NUC via LAN IP address.

At first I thought this was due to a Windows update, but after uninstalling the update the problem persists.

I realize this probably isn't a TV issue per se, but I would be grateful for any suggestions to try to get this working again.  It's really frustrating to get out in the field and not able to do what I went there to do, simply because I can't log in to the NUC.