[u]MP3 Diags[/u] found a few potential issues including:
Unknown steam found. Since other streams follow, it’s possible that players & tools will have problems using the file. Removal of the stream is recommended.
In the tools I clicked “Remove unknown streams” and Audacity was able to open the file.
Notes:
MP3 Diags is “destructive” (any changes are irreversible) so make a back-up your file before playing with it.
Audacity only uses LAME for creating MP3 files. It uses something else for opening them.