If you cannot add a payment method to Knewton.com, please verify:
- You are only using a debit or credit card. We do NOT accept prepaid cards or gift cards.
- All your information is correct, including: first name, last name; card number, expiration date, and CVV.
- The billing address on your subscription is correct and matches the information tied to your credit or debit card account.
- The card is not expired.
- There are no extra dashes or spaces in the card number.