The client logs show playback occurring at 11/28 around 1:00 AM. Your father’s Fire TV is 12 hrs behind. I’m not sure this is the problem but something to get fixed either way.
I do see the error when trying to playback certain content. The failures are happening when the audio codec is something that is not supported. In the case of Spider-Man, it’s TrueHD. The Fire TV is asking your server to transcode it to EAC3, which is then failing. I’m not sure why it’s failing, that’s something I still need to investigate. Your father should be able to get around this by changing the audio settings on his Fire TV (the main devices audio settings, not inside the Plex app) to disable using EAC3 (aka Dolby Digital Plus).
