Blank Page after confirming payment in "Recurring Payments" option

Hi Wpmudev, I have a problem after confirming a payment in "Recurring Payments" option in my website http://www.nowpocket.com/classifieds/checkout. In fact when I click on "Confirm Data", I get a blank page. Why? How can I fix it? P.S. I chose "PayPal Live" and my account is Business.