MP3s won't play

Many MP3s downloaded from Youtube edit perfectly in Audacity. But from “Live from Daryl’s House” these files won’t play. They will load, but trying to play them only activates the interface for a moment, and it goes back to inactivity. I tried using the MP3 repair utility for Windows that removes 26 milliseconds from the beginning of the file. This produced no change.Any ideas? Audacity 3.1.0 on Ubuntu desktop CPU i5.

Ubuntu 20.04.3

That’s surprising. Do they look like normal audio tracks when imported?

What happens if you apply “Tracks menu > Mix > Mix and Render” to the track?

Yes, they look normal. The Mix and Render does some work on it, but afterward it still won’t play.

Do the files play in your usual media player?

Yes, though they have a few seconds of silence at the beginning.

Can you export the “bad” MP3s as WAV?

Yes, it will export fine as WAV, and play by the Ubuntu player, and reopen in Audacity, but still won’t play there!

but other files do play?