What does "Payment Method is set to use credit cards" mean?

If you're receiving the following error it means you have a Payment Method set to require a Credit Card:

"Your payment method is set to use credit cards, but we did not get a credit card number. Retry this payment with a credit card, or please modify this payment method in the Settings to NOT require a credit card."

To fix this, go to Admin > Payment Methods and update these to not be set to Payment Type 'Credit Card':

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