Checkout errors

Look at the following help desk articles if you experience errors during the checkout process.

1. Parameter Invalid Empty
2. The Customer Must Have an Active Payment Source Attached
3. Stripe Payment Error: This account cannot currently make live charges. If you are a customer trying to make a purchase, please contact the owner of this site. Your transaction has not been processed
4. Sorry, This Product Cannot Be Purchased
5. Common Credit Card Decline Codes and Next Steps
6. The Zip Code You Suppled Failed Validation
7. Sorry, Your Session Expired
8. Email Address is failing validation because of my browser's autofill feature
9. What to do if your order/payment was declined/failed, but your bank shows a pending charge