Unable to make an HTTP REQUEST (POST) Using Macrodroid to Access PaLM API

Question

When trying to make a http request to PaLM API I just get the output:

{
  "error": {
    "code": 401,
    "message": "Request had invalid authentication credentials. Expected OAuth 2 access token, login cookie or other valid authentication credential. See https://developers.google.com/identity/sign-in/web/devconsole-project.",
    "status": "UNAUTHENTICATED"
  }
}

I am unsure what the error is referring to and how to resolve it.

I attempted to create an OAuth id but I am still not sure how to implement it in to the http request.