Because during the system upgrade. Bank of China issued an announcement on its official website regarding the suspension of credit card services during a system upgrade from April 30 to May 2, 2022. Bank of China all-currency credit card processing will be suspended, and cardholders' use of Bank of China credit cards will be affected to a certain extent. The types of suspended services include credit card application, customer information modification, card account installment, special installment, etc.