Http request 401 Unauthorized - User authentication is required

Yes but there must be something in the request from postman, that is not correct in the request from the http-request node. Try this one. Perhaps the server requires you to send a user-agent in the http header. That will most probably be available in the postman request (please check that!), because your browser will fill that header field with information about the browser. Please try to set the user-agent field, as described in the link that I have provided!