spree/spree_paypal_express — Issue #39: Gateway Error: Security header is not valid
Author: MachineTobe
Created: 2012-02-29 12:16:41+00:00
State: open

Hello Guys,

I've installed the gem, configured everything (step by step like described in the readme-file) but when I want to pay via paypal (clicking on the paypal express button in the cart) i got the message 'Gateway Error: Security header is not valid'.
I used the credentials from my Selling-paypal Sandbox account (tried them hundreds of times). What's the problem in this case? Would be great if somebody could help me.

Thanks, Tobi