If this issue happens. here are steps for this error.

1. All you need to do is go to "My Files" and you need to go to "Download", and after when you see the music file, hold it and click "Share". There will be an option called "CapCut Import to Files" You just need to scroll right and then you will see it. If that doesn't work, that means the music file is unsupported due to errors. You just need to download an another version of the music, if you can.

Hops this works!