I took two logs. One from FireTV with 8.2.1 which works.
Second one from FireTV with Plex app version 8.4.2 from Amazon App Store. Still not working.
I tried transcoding on/off, new player on/off. None of it worked.
I am also attaching Server logs (they are not time sync) while verbose logging enabled on server I tried macOS client app ( 1.16.0.1364-da192ff7 , July 30, 2020) and FireTV client app (8.4.2 from Amazon App Store on fireTV) tested both new player enabled and old player. All of them not working. I can see in server some TLS errors. so whatever changed in the recent code may have broken the TLS handshake for MacOS and Android TV versions when they run over Double NAT.
working version 8.2.1 logs.txt (48.5 KB) problematic version 8.4.2 logs (firetv appstore).txt (232.2 KB)plex server logs.txt (281.3 KB)
Just to remind you my server works fine. It is hosted in the cloud and I reach over Internet. Apple TV and mobile apps working fine. MacOS home theatre app and using over Chrome browser works as well. I also know Samsung TV player also work from a friend using my server. FireTV client app any version above 8.2.1 stopped working. MacOS new client software also not working as I explained.