ShopSite Knowledgebase

PayPal Express Checkout: Beginning about April 30th, 2021 shoppers get "Security header is not valid" error

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I am using PayPal Express Checkout in my ShopSite store, and beginning approximately April 30th 2021 shoppers are receiving an error message like the following when trying to checkout using PayPal in my ShopSite store:

"PayPal Express:

Message: Authentication/Authorization Failed (10002) Detailed Message: Security header is not valid"

What is the problem, and what can I do about it?

Merchants using the 'Accelerated Boarding' authorization method in their ShopSite's PayPal Express Checkout settings have reported shoppers experiencing this error. To see if you are using Accelerated Boarding go to Commerce > Payment and click the Configure button in the PayPal section and look for the 'Authorization Method' setting.

We have contacted PayPal to see if they will fix their Accelerated Boarding authorization method, but merchants experiencing this issue should switch to using one of the other authorization methods, we recommend the 'API Digital Signature Authentication' method. Note that you will need a PayPal Business account to use this method. If you do not have a Business account the first step is to upgrade your PayPal Personal account to a Business account. One way to tell if you still have a Personal account is to login to your PayPal account and if there is a gear icon in the upper righthand corner it is a Personal account, but if it has been upgraded to Business your login name and profile picture icon will appear there instead of the gear icon.

To get the API Username, Password, and Signature required by this method from your PayPal Business account, login to PayPal and go to Account Settings > Account Access (OR Website Payments) > API Access >NVP/SOAP API Integration (Classic) > Manage API Credentials and select 'Request API Signature'. Once you click 'Agree and Submit' on this screen, click the 'Show' link next to the three credential items, and in a separate window/tab go to your ShopSite backoffice menu Commerce > Payment > PayPal > Configure and select the 'Use API Digital Signature Authentication' authorization method and copy and paste the three credential items from the PayPal menu to the corresponding ShopSite fields, then click 'Save and Enable' at the bottom of the ShopSite settings menu (and 'Done' in the PayPal menu).

If you still get the 'Authentication' error when trying to checkout with PayPal after this, try re-copy and pasting the API Signature credentials again from your PayPal account to make sure that the correct credentials are being used.

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Article Details

Last Updated
12th of May, 2021

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