REST driver and Google Enterprise License Manager API

I´m working in a REST driver to associate a license of a Google product to a user using Google Enterprise License Manager API. I´m not being able to configure the authentication to Google Cloud Platform. I´m getting the following response back. Does anyone have done it?

<header content-type="application/json"/>
<value message="Unauthorized" status="401">{ "error": { "code": 401, "message": "Request had invalid authentication credentials. Expected OAuth 2 access token, login cookie or other valid authentication credential. See ">", "errors": [ { "message": "Invalid Credentials", "domain": "global", "reason": "authError", "location": "Authorization", "locationType": "header" } ], "status": "UNAUTHENTICATED" }}</value>

This is what I have done so far.

- Created an OAuth 2.0 Client ID on Google Cloud Platform.
- On the REST driver, subscriber channel parameters, I configured the OAuth2.0 option for Authentication Method.
- Also on the driver configuration I selected Generate Bearer Token on OAuth2.0 Token Management field.
- I provided the Access Token URL,
- I used the information of the OAuth 2.0 Client ID that I created on User Name and User Password fields on the driver subscriber parameters.

I also tried to use Enter Bearer Token on OAuth2.0 Token Management field, but I was not sure what to provide on the Bearer Token ID. I tried the OAuth 2.0 Client ID name. It did not work. I got the same error as I mentioned above.

Any help is welcomed. Thanks.