This problem took the longest to figure out.
Plex app opening and closing on a Samsung smart TV Both of which I was able to figure out with a little help from the web. The second, the app would open but not connect to the Plex Media Server. First, the app would open and then immediately close. I had a couple of problems with my setup that took a couple of hours to figure out. Troubleshooting Plex on a Samsung smart TV