How to accept direct card payment on PayPal Test on a WP e-commerce based website?

Learning to build an e-commerce website based on WP e-commerce <snip/>, payment is supported by PayPal.
When I tried to use Paypal Express , it showed
“SetExpressCheckout API call failed.
Detailed Error Message: Security header is not valid
Short Error Message: Security error
Error Code: 10002
Error Severity Code: Error”

When I tried to sue PayPal Pro, it showed: “Security header is not valid”

My Paypal sandbox setting:

  1. A seller account
  2. A buyer account
  3. A PayPal Payments Pro account
  4. A buyer In-Store account (for Payment Card Credentials)

If I still couldn’t work out in Sandbox mode, I get to open a real one for test.

Thanks for reading.

Getting Security Header is not valid error usually means:

  • You are using the wrong API credentials
  • Or you are sending the right credentials to the wrong environment.

First find out whether you need an API signature or API certificate. Then login to your account and generate the API credentials and specify that in your module.

Lastly, check that you are sending the transaction to the live server and not the sandbox server.