I have created checkout page but it's not working when I test it. What is the paypal client ID?

When testing, I get an error message: Payment error Client authentication failed. Why was I asked for a client code? I'm not sure what it means.

Please help.

Thank you.

This error usually occurs when you enter wrong Client ID and Client Secret. Please make sure that you've entered correct details. You can get the Client ID and Client Secret at https://developer.paypal.com/.

Use this guide for more information about PayPal Checkout integrating, getting Client ID and Client Secret: https://www.jotform.com/help/542-How-to-integrate-PayPal-Checkout-with-your-form