To avoid interruptions to your subscriptions and purchases, verify your payment information or add a new payment method. It keeps telling me this

I keep trying to add my venmo card to my apple pay and every time I try to it says “To avoid interruptions to your subscriptions and purchases, verify your payment information or add a new payment method.” But then doesn’t let me verify it or how do I because it’s not letting me buy anything with my apple balance which is what I’ve been trying to do the whole time but it says I need a credit card but won’t let me add one.