Got the link, created an account and went to checkout.
Entering the "standard" Visa test card 4111 1111 1111 1111 with an 02/2017 expiration date and 111 CVV, I receive an "Internal error" message back at the checkout_payment page. Not the most descriptive error, but not a blank screen.
Was there some other credit card that you tested with? PM me if necessary; I'll check it out in the morning.
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