Error when creating JWT Token

Question

As I am on my way to switch from using the legacy header authentication method to the JWT Token method, I have used the following example found here.

However, I get the

Answer 1

After more investigation, the reason with such an error is that I was not generating the Authorization Code Grant prior to executing my code. Based on the information found here, I had to perform the following HTTPRequest example :

GET /oauth/auth?
  response_type=token
  &scope=signature
  &client_id=YOUR_INTERGRATOR_KEY
  &state=a39fh23hnf23
  &redirect_uri=http://www.example.com/callback

Once it is approved, then I can run my code successfully. In the end, the initial error message is really misleading (I might argue it could be considered a bug ?).