Nvidia shield tv playback error: Plex Server: Conversion failed. A required codec could not be foun



Hello team supoort.
I bought yesterday an nvidia shield 2017. I set up plex server and it was working fine with external video un til I received a message asking me if I want autorise passtrough audio. I answered yes and since then I have no video anymore playing.
I went to settings and I disable it and the result was the same.
Then I enabled it again and video works but not sound.
I tested with videos decoding Ac3 and it does not aniwork.
I tested it on the web, and result is identical.
I do not understand why this is happening.
Joint to this message, log and database files
Thans a lot for your help


any idea about this issue. Anyone can help me?