Export to mp3 format

I want to cut a music (in mp3). It works.
Then I put this music on the Timeline. OK
I want to export this music to mp3.
There, it no longer works.
What should be done ?
Thank you for your help

Are you using the Export preset for MP3?
Because it works just fine here.

Super, thank you very much, that’s it.
Here are the screenshots and it works.
thank you very much