Glad you have things working.
I do not know the root cause of the problem, but it seems to have something to do with secure communications between current Android/AndroidTV clients and older versions of Plex Media Server.
Your client log had several of these entries: [FFmpeg] [ERROR] [tls @ 0x2aac9282c0] Peer certificate failed verification
I’m running current releases on my Plex server, Shield client, and FireStick 4K client. I cannot reproduce the problem and the log files from the Shield & FireStick clients do not have the Peer certificate error message.
The error messages are most likely gone from your Shield client logs as well, now that you’ve updated things.
@ofczianka If you cannot update your Plex server, keep following the An error occurred while attempting to play this video check the connection and try again thread. A Plex employee is active on that thread and working to find a resolution.
If you have not already done so, try disabling secure connections on the server (Network → Secure Connections = Disabled) and client (Settings → Advanced → Allow Insecure Connections = Always), and rebooting both the server & client. Granted, it is a workaround, but it has worked for some users.
