[User 224999]

Here is my full log file : https://paste.ubuntu.com/24859326

Hmmm, I think I have to add some more debug lines to the code because I can't find what's wrong in your log.
The request is received by the audio proxy and after that it fails so somehow the audio stream is not retrieved from librespot.

Can you test 1 thing ? In the plugin's settings you'll find an option like "Buffer entire track"
Please enable that and try playback again. Maybe some systems cannot handle that the audio is sent chunked to the kodi player.