One Page Checkout final step reverts back to shopping cart for credit card payments.

hello all,

I currently use shopware 5.5.3 there is no patches are installed. The checkout used to function properly and once you hit proceed to checkout, the customer gets a confirmation that the order went through. However, recently when you hit the final stage(address and payment info has been collected at this stage) which is proceed to checkout, it takes the customer back to the shopping cart to restart the process again instead of giving a confirmation number. The credit card was processed without one-page checkout plugin. I have following error message in the payment page.“Ihre Kreditkartendaten sind ungültig”.