The system does not work with credit cards.

The system does not work with credit cards.
When I select payment cards, it remains in standby and the payment fails. However, if I log in with PayPal, it works fine. But the credit card does not work. A customer informed me that they were trying to place an order but couldn’t because the payment was blocked.
I tried it myself and found that it does indeed get blocked. I receive a notification from my bank, which I authorize, but then it freezes, and a notice appears stating that the payment failed.
What should I do?