I have an Nvidia Shield TV with Plex installed. I also have the Windows app with which I manage libraries, etc. While using the Windows app, it it showing that the Shield is unavailable. I also have the app on my Android cellphone and everything is fine. I’m hoping it is just a matter of some setting being set improperly, but I am not having any luck figuring it out. Hoping someone can perhaps walk me through some troubleshooting. Nothing I have found in this topic has worked.
If it’s playing on any other device but not the shield. Try checking to see if there’s an update to Plex in the Google store and try rebooting the Shield too to see if it helps. After reboot make sure all drives you use are reconnected before trying again.