Plex recently updated their app - it sucks! Some things will not be in the search on your app, but can be found if you look in the library...sorry...you can also check here...
ALSO, some videos might not play smoothly even on fast connections. If you're running into buffering, playback errors, or other weird behavior, it's not just you! Submit a Plex Problem Report below, and I can most likely adjust things on my end while we wait for Plex to fix their bullshit. 🙃