Sync Error CCO

Dear Community,

one Client has problems syncing receipts where vouchers were used to pay with.

The Error looks like: "com.sap.scco.util.exception.XState: Vouchermaterial ID: GS for B1 Field "CreditCard" was not found in voucher material Id settings.."

Checking via Customer Checkout Monitor doesn't do anything because I can't find the receipts there.

The Connection Test from the POS itself works. And also does the syncing work for Articles and so on.

Only for receipts I'll receive said error.

What should I do here, to get the receipts posted again?