PayPal error: Security header is not valid

🤔 Problem

I have added my PayPal information, but when I run a test reservation, it says “PayPal error: Security header is not valid”.

🌱 Solution

This error normally happens only when you have not entered your API credentials correctly, for example if you have entered the sandbox API instead of the live API. You should retype your API Username, Password, and Signature and make sure that you have correctly set “Use PayPal Sandbox” in HBook > Payments.

  1. Please check again your Username, Password, and Signature

  2. Please make sure that you are not mixing Live and Sandbox credentials