Conversion failed. A required codec could not be found or failed to install.

I recently purchased an NVIDIA SHIELD to use as a Plex Media server and found that the files I have in MP4 format seem to run the smoothest. Many of my files are .MKV so I used VLC to convert one as a test to see how it would work. After converting the video I now keep getting this error “Conversion failed. A required codec could not be found or failed to install.” not only for that specific movie, but for pretty much every movie. I tried analyzing the content again, and that did not work. I deleted the converted file in case that was causing some sort of issue, still nothing. I even deleted the entire media library from Plex and reloaded it, still no luck. Any thoughts would be highly appreciated.

Logs attached

Thanks

What is your PMS version? You may need to manually update via play store on
web browser to push it. From then on updates should be automatic