I am getting invalid security header message when trying to process refund. i Have followed instructions below, i have checked with server host, removed any spaces... still not able to process refunds - HELP please!!!
Here's how to request or view API credentials from your PayPal Account:
Log in to your PayPal account.
Click Profile near the top of the page and then click Profile and settings.
Click My selling tools.
Click Update next to "API access."
Scroll down to "NVP/SOAP," click "Manage API credentials."
Select "Request API signature" or you can view the API Signature if already requested
Click show on all options
Copy and paste the credentials into WooCommerce (Make sure there are no spaces before or after the credentials as this will cause the Security Header Invalid Error Message)
From the WooCommerce (3rd Party Shopping Cart) Documentation :