Checkout works "live", but not "sandbox"

The site is currently set to use PayPal Express Checkout. While the store is set to the "live" setting, clicking on the "continue to checkout" button navigates the browser away from the store site to the PayPal page, to continue editing buyer information such as credit card number, address, etc to complete the purchase. However, in "sandbox" mode clicking on the "continue to checkout" button returns the following error:

"10002 - Security error - Security header is not valid"

and the browser does not navigate away from the store site to PayPal.

The glitch appears to be only while the store is in "sandbox" mode, as setting the store to "live" navigates to PayPal, as expected. I wish to be able to test the payment gateway without having to make a payment, as I am building this site for a customer. The site is online now. If you wish to do so, you may run a test yourself. The site is currently is "sandbox" mode.

  • Daniel
    • New Recruit

    My apologies for posting before THOROUGHLY searching the support community. I just read a reply to a previous post with the same issue. I neglected to search the forum using the error string. My bad!

    Thank you so much for your prompt reply. Literally less than five minutes after I posted my question, and while I was logging into PayPal to get the sandbox credentials.

    Kudos to WPMUDEV support!!!


    Update: I set up a PayPal Developer account, and acquired sandbox API credentials. I added the credentials to Marketpress, and the whole test checkout process worked without a hitch. THANKS AGAIN!!!

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