Taking China Merchants Bank's credit card as an example, the common reasons for credit card swiping failure are: 1. The credit card is not opened; 2. The transaction password is wrong; 3. The credit card limit is unstable; 4. The available credit card amount is insufficient; 5. The credit card limit is limited. You can log in to credit card online banking and click Card Management-Card Limit Adjustment to make adjustments. If you encounter other problems in use, please call the credit card customer service hotline for handling.