My Brother machine doesn't feed a card for scanning.
A card may not be suitable for scanning from the Automatic Document Feeder (ADF) of the Card Slot.
Follow the steps applicable for your case.
If you cannot scan a card from the ADF:
Insert a card into the Card Slot and try scanning a card again.
If you cannot scan a card inserted into the Card Slot:
Place a card in the ADF and try scanning a card again.