Pas de son après exportation

I have used an oldest version of Audacicity 2 years ago for getting music from vinyl and i have .wav sound files hearing with VLC.
Today, with Audacity 2.3.3 when i export sound from project in .wav or in .mp3 the file is created but when i open it in VLC length of playing time is correct but no sound can be hearing.
Can you help me ? (si possible en français !)
I use linux ubuntu 20.04. LTS, Audacity 2.3.3 from PPA

Solved ! ffmpeg was not correctly installed.
For solve, in terminal i type :

sudo apt update
sudo apt install ffmpeg

afterr export in audacity it’s OK.

Can you hear it in Audacity?

Can you hear anything else in VLC ?

==== translated by Google =========

Pouvez-vous l’entendre dans Audacity?

Pouvez-vous entendre autre chose dans VLC?