Trying to buy books through PC only works on mobile app

Hello,

I have tried to buy books on the website and I get to the payment confirmation and get an error stating that something is wrong. It does not specifically highlight or state what is wrong. I go onto the mobile app for D&D Beyond and can buy the books that way but the pricing is WAY different. Is there a work around to get the website to process my purchases vs my app?

Been having issues with the marketplace's checkout system since the "new" markeplace page was put in place; never had any help; just vague finger-pointing at my payment processor/financial institution... which says they aren't causing it either.  So... -shrug-