The credit card cannot be used for the following reasons:

1. The credit card balance is insufficient, and the consumption limit is greater than the credit card limit, so it cannot be used.

2. The POS machine network is unstable. You can try a few more stores.

3. If you enter the wrong password multiple times and your password is frozen, you need to go to the bank to unfreeze it.

4. The maximum daily transaction amount is lower than the credit card limit this time.

5. The bank determined it to be a malicious cash-out, and the card limit was limited.

6. Some banks require a card swiping password to make purchases with the card. Check whether it has been activated.

If the above situation does not occur, it is best to contact the bank customer service as soon as possible to inquire.

Extended information:

Since the card is sent by mail after the credit card application is approved, there is no guarantee that the recipient is the applicant. In order to protect applicants and banks from fraud losses, the credit card has set up a card opening procedure before it is officially launched.

Card opening is mainly done by phone or online. The relevant personal information provided during the application is checked. Once the card is met, the card opening process is completed. At this point, the applicant becomes the card holder and can officially start using it after signing on the back of the card.

There are usually three ways to activate a credit card: The first is to activate through the bank counter where the credit card is located, which requires the person to come forward and the original ID card and credit card.

The second is the service phone activation method. You need to call the 24-hour customer service hotline shown on the back of the credit card for activation. The third method is to activate online. Log in to the online banking page of the Bank of Communications credit card and enter the cardholder's card number and password to activate.

Baidu Encyclopedia - Credit card swiping