[Note: If you're having a different issue when you're trying to complete a purchase, please see this article.]
It's rare, but sometimes when people try to make purchases using PayPal, the purchase window just shows a blank screen when they click to complete the purchase.
In our testing, we believe this happens because you need to click a button in the purchase window to accept cookies.
If you don't click the button to accept cookies before completing the form, you may just get a blank screen.
If you don't see the button to accept cookies before filling out the PayPal purchase form, try closing the purchase window and clicking the PayPal button again, or just reloading the page.
If you discover you have been charged for a purchase that has not been completed, please email us at hello@leanpub.com, making sure to let us know what email address you were using to try to complete the purchase! That way we can reverse the charge for you.
Our apologies for the difficulty here!