Add to Cart button does not work. View Cart shows "Your cart is empty"
I'm using a PayPal Business account.
I've had a Business Pro account for many years but just starting to use Add to Cart buttons now. I've got a properly formed "Add to Cart" button and "View Cart" button. The html for both on my website matches is correct, but nothing gets added to the cart. The page on which both buttons reside is secured (https).