This is embarrassing but... I chose a preset I want to purchase, I got it in my cart. When I click on "Proceed to Checkout", it takes me to the My Account page. It just dead ends there, with no way to complete my purchase. I've already put in my credit card that shows under My Saved Cards, but if I click on Stored Payment Methods that page just says: "You have no stored payment methods."
It's kind of weird that a company makes it difficult for me to give them money... :D
I'm on a Mac using Safari with no content blockers.