FAQ (PayPal Express Checkout Errors)
Q: Declined 10413
A: PayPal Express Checkout-Declined
Declined 10413 : The totals of the cart item amounts do not match order amounts.
This error could appear when you first put items in cart and calculate already shipping cost, Taxes etc. and then instead of paying by credit card, you click "Paypal Checkout" option. Since "Paypal Checkout" do calculate its own shipping charges based on address on paypal account, therefore total amount already in cart (inc.shippinng & Taxes) does not matches to item cost in Paypal Checkout. To resolve this, click second time on "Paypal Checkout" so that session is reset or delete your items in cart, add new items and then click directly on "Paypal Checkout"