Hello @smarts301,
Thank you for posting to the PayPal community.
The "error:10002: Security header is not valid" you are experiencing is usually caused by incorrect API Credentials or API permissions for third-party calls. Please make sure that you have entered the correct credentials, including your API username, password, and signature. Any typos or incorrect information can cause authentication failures.
If you are still experiencing the issue after verifying that info is correct, please create an MTS ticket via the following URL: https://www.paypal.com/mts. Please provide any shopping cart software you are working with, and a copy of the API request and response if available when you submit a support ticket to help them resolve this issue in the shortest amount of time possible.
Sincerely,
John
MTS
PayPal
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