1. Try formatting the card on your computer first.
2. Format it to "FAT32" or "exFAT32".
3. After formatting, insert the card back into the device without powering it on.
4. Power the device on and check if it recognizes the card.
5. If the device still can't recognize the card, try another card to see if it's recognized.
If the new card is recognized, the original one might be damaged. Consider getting a new card.