How can I set the order number to bump up one if the customer gets a failed transaction? The page that appears after a failed transaction, invites the customer to order again (without identifying the problem). So, we often have second attempts, which are rejected by the credit card processor, because of duplicate order numbers.
In testing, even after leaving the site and returning, my test product was still in the cart and when I tried to reorder from scratch it still was rejected due to duplicate order number.
That’s a payment method issue. What processor are you using? Generally the payment processor code in the cart will append a _1, _2, etc. for subsquent attemts while leaving the actual order_id alone.