Videos play in Plex but get HTTP 500 with Infuse on Apple 4K TV

A few videos will play in Infuse but most of them will not. Posters and episode information display fine. I’ve verified that permissions and ownership are good. (plex:plex and 775) I’ve cleared cache, uninstalled the app completely, rebooted the Apple TV box. What else can I do?

I use Plex mostly but I would like to use Infuse more often.

Plex Server on Linux Mint 22.1
Plex Version 1.42.1.10060
Infuse 8.2.2 (5291)
tvOS 18.6

This may be related to Plex Relay.

Plex Relay is a service provided by Plex for remote streaming. It has a low bandwidth cap so can lead to playback issues.

It’s possible to avoid using this by disabling the service on your server in the Network Settings section as described in this guide. Network | Plex Support

If you are streaming locally, Plex may be incorrectly routing traffic through its relay service (which is not necessary at all on a local network). In this case, you may try restarting your Plex server.

Your suggestion about remote access gave me a hint. I seem to have solved the problem by making two settings changes. To test, I tried movies and TV shows that would not previously play.
This is how I seem to have solved it.
In Plex settings, I changed the network type to IPV4 instead of both. I added a netmask for the LAN (192.168.12.*). I also changed the preferred network interface to be the physical. I unchecked remote access. I can’t do port forwarding from outside my LAN because T-Mobile uses CGNAT and my gateway is IPV6. I use Tailscale to get around this.

I recently took a trip to Florida and was able to play several movies through Plex without issue. I didn’t check to see if they were being transcoded, however. I expected Infuse to be able to play movies/shows on the same LAN.

That’s great to hear! Thanks for following up.