It may be a transaction suspected of cashing out. If several large integer sums are swiped on the same POS machine and the same IP is repeatedly paid through the online payment platform in a short time, the system will refuse to pay, and the credit card itself has problems, such as insufficient credit card balance, the credit card swiping amount exceeding the single/daily/monthly payment limit, and the credit card is stopped. At this time, using a problematic credit card to pay by credit card will also lead to refusal to pay.