Direct Play not playing on Fire TV

When I stream from my Plex server to my Amazon Fire Stick and it streams with direct play it plays the video about 3 seconds and then hangs and says that there is not a fast enough network connection. If I force the video to transcode with dropping the quality or adding subtitles it streams fine.

I have had the same issue on multiple Fire Sticks on different networks including my local network that has the Plex server also.

If I run Plex from the Firefox app from the Fire TV it works, but is just a little janky. Any ideas on how to get it to either not Direct Play or to get direct play to work?

As @trumpy81 writes, make sure your media is compatible with your players.

AFTV capabilities vary by model. The pendant (latest) supports H264 High@4.1. Previous models are High@4.0. H265 support varies from none (original) to 4K HDR (latest).

FireTV Tech Specs

Set Display Information = On in Plex client settings on AFTV. During playback, pull up on-screen controls (pause, forward, etc). Status will be displayed in the upper left corner. It will show if audio/video is transcoding & give a reason. This is available on Android & Android TV devices. Have not see it on other clients.

Also, make sure your AFTV audio settings line up with the attached TV or receiver. The default, IIRC, is “Dolby Digital Plus Automatic.” If attached device does not support DD+, this can force an audio transcode to stereo. If this happens, try “Dolby Digital over HDMI” instead.

Yeah, I was seeing this also with my FireTV also. Even though it would state “not fast enough network”, if I started the stream again, it would usually play just fine then. I eventually decided to spend the money and grab an Nvidia Shield TV, and now life is good again as everything direct plays/streams and is very fast!

@“Brian.Watson” said: eventually decided to spend the money and grab an Nvidia Shield TV, and now life is good again as everything direct plays/streams and is very fast!
I’m sure that the Shield is great but a cheaper alternative would have been to buy the MrMC app at modest cost from the Amazon app store. This is basically Kodi without the naughty addons & with a Plex client (among others). It will Direct Play everything including 4K HDR & does audio HDMI passthrough so exotic HD audio streams can be handled by an AV receiver. The final bonus is that the Plex client looks like the old Plex Home Theatre so doesn’t have the awful Android TV UI that the official Plex client for AFTV moved to last year & that the Shield is also lumbered with. MrMC is also available for the Nvidia Shield if you would like a nicer UI for Plex plus much more control over audio & video playback with all the ability to adjust settings in the Kodi player.

I found this thread while trying to debug an issue with my home setup.
Plex is running on a Synology DS918 I have no issues with playback on phone, tablet, browser, PS4 however my FireTV(s) have problems on a lot of my media.
Smaller files (480p ac3) are fine but larger ones such as 720p h264 (AAC stereo + AC3 5.1 ) are very slow to start and then freeze after a minute or so.
If I change the video quality from “Play Original Quality” to “Convert Automatically” then it works fine. I cannot find a way to do this automatically and have to change this setting every time I play a video. It sounds like this issue hasn’t been fixed, unless I’m missing something.
Did anyone work out a solution that didn’t involve replacing their FireTV devices?