Have you tried the card in another device to make sure it’s not the card?
If you can get the card to work somewhere else, maybe it’s corrupted. You can try formatting it.
Other than that, you can try formatting the player, to wipe its database clean. Maybe it’s just not recognizing it because of its own database being corrupted.
in the end I discovered that I could still format the card through the player. And now I look here and see the same suggestion. I’m still not sure what went wrong but thanks for the reply anyway.