p is not a function error using the example downloaded from Paypal

[jmozzart]

I am working on Advanced Integration. No changes in the downloaded code from Paypal except my client id and client secret but I got this error. By checking the browser console, it is occurring after making a request to "https://www.sandbox.paypal.com/v2/checkout/orders/03S74492AF553953B/confirm-payment-source" (

Failed to load resource: the server responded with a status of 400 () ). I don't see any errors in the server.js.

Please help me. I need this to finish as soon as possible.