What does the smart card in the canteen mean by err-27?

System exception is in protection state. A smart card in the canteen is a card for eating in a restaurant. Err-27 indicates system abnormality, and err-27 indicates that system abnormality is protected. A chip is integrated in the all-in-one card, which is usually very thin, within 0.5mm, with a diameter of 1/4 cm.