My player will no longer recognize info of some music files.

I have a model M250, and it’s great it even use to recognize correct artist/title/album info on all my music…until this morning. For some reason one some music files it recognizes the title and album, but the artist is “unknown”. What do yall think happened to cause that? It’s very frustrating, i can’t imagine what i done wrong to make it lose info. My PC recognzes the artist…but not my devise like it used to.