The reasons for repayment failure are as follows:

1. Input error: Personal information or bank account number is entered incorrectly. It is recommended to check the correct information before entering it.

2. Banking system problem: It is likely that the credit card issuing bank system is in the process of upgrading or the service is too busy. The cardholder can refresh and try again.

3. Abnormal credit card account: Your credit card may be frozen, canceled, or needs to be activated, etc. Cardholders are advised to call the bank service hotline for processing.