Why did I get API error code 10485?
PayPal returned API error code 10485 - User did not authorize the payment.
The payer wasn't redirected to PayPal, so the user didn't authorize the payment.
Redirect the payer to PayPal after calling the SetExpressCheckout API command to complete the payment. To learn more about identifying your Express Checkout token and redirecting your buyer to PayPal for approval, see Steps 2-3 of How do I create a one-time payment with Express Checkout?