I think there is a problem with the payment system using a credit / debit card. When I make a payment there is a redirect page that leads to an error payment system where my card has no problems. Please check back on the rewards page for purchasing gift cards using a credit card.
@KeylayF236331 We are aware of an issue that impacts some people who try to checkout with multiple items in their cart, but in that instance, you do not see a cart total so you cannot proceed to checkout. That doesn't sound like your issue.
Log out of your http://AARP.org account and log back in. Clearing your cache and cookies may also do the trick so you can complete the payment. Let me know if this helps.