Security header is not valid using express checkout

Hi Guys

I have an issue with eCart and Express checkout.

History Brief:

Setting up eCart with PayPal Standard using Express Checkout.

Set up ecart as PayPal Pro using Express Checkout credentials.

Once created, removed Credit Card details from checkout.php

Added Local Checkout Response for both Process and Authorise

When I choose Paypal express checkout I get Security header is not valid.

I have already changed the PayPal Express checkout API Credentials in my PayPal account and get the same output when submitting order.

If anyone could help with this i would be grateful

Kind Regards

Jonathon

the security header is invalid error means there is a problem with the API Credentials.

There are 3 places the API Credentials are added for Express checkout:
1 on the checkout page in the Authenticate transaction for PayPal Express

2 on the pp_confirrn page in the get payer profile and the process transaction with paypal express, make sure to change the API credentials in all 3 places.

Hi Jason,

I have checked and made sure all API Credentials are correct in all 3 places and tested.

I am still getting the same error.

Regards

Jonathon

This can happen if the Sandbox option is enabled and you are using live API Credentials or Vice Versa.


It can also happen if you have not accepted the billing agreement with paypal.

sometimes, paypal just generates bad API credentials, if all else fails, generate new ones.

Hi Jason,

I have accepted billing agreement with paypal and i have generated 2 sets of API credentials and tested both.

As for sandbox option. i am unaware of where to find the sand box option i could not check.

Found sandbox tickbox in Server Behaviors and removed.

Will post back after test

That was the answer. removed tick box from Server Behaviors panel on checkout page and all is sweet.

Again Jason its the little things that make all the difference,

Very much appreciated.

Jonathon

glad to hear it is working.

Hi Jason I think I spoke to soon

When going through the checkout procedure I complete right up to the final stage and I get "Security header is not valid" on the pp_checkout_failure.php
page.

I am so close i can smell it,,,, :(

Any further help would be appreciated

Jonathon

make sure the api credentials in the Process transaction through paypal express checkout server behavior are correct and that the sandox option is not enabled.