1. Incorrect credit card password: Many times, credit cards cannot be swiped because the password entered is incorrect. If the password prompted by the POS machine is incorrect, it must be a credit card transaction password error. If so, the cardholder should think about his credit card password and re-enter it. Because once the credit card password is entered incorrectly for three consecutive times, the system will automatically lock the card to ensure the security of the cardholder's funds.

2. The merchant sets a certain credit card limit: sometimes the merchant sets a credit card limit, so there will be an obvious enough credit card limit, but it will prompt that it exceeds the consumption limit of the day or the number of transactions of the day. According to the requirements of the regulatory authorities, credit cards are not allowed to be used in non-consumption areas, and the safe has also clearly stipulated the trading limits of certain types of overseas merchants. Therefore, in order to ensure the safety and compliance of cardholders' card use, banks will limit the transaction amount and transaction times according to different merchant types. In addition, some online merchants have a single or daily cumulative limit of 1 000 yuan, subject to the announcement of the merchants.

3. Abnormal credit card status: the credit card has not been repaid for a long time, or there are risks, so it is impossible to swipe the card; Putting magnetic stripe cards together with electronic products such as mobile phones may lead to degaussing of credit cards, and similar situations may lead to abnormal card status and transaction failure.

4. Poor line of communication system: If the card is used correctly and the credit card line is sufficient, it is probably a system connection problem.