Google Gropus API with old account

Question

I need to modify group settings with Google Groups API on my old google for business account. I use web request:

PUT
https://www.googleapis.com/groups/v1/groups/<group_id>
request body: {
    "whoCanPostMessage": "ALL_MEMBERS_CAN_POST"
}
headers: {
    'Content-type': 'application/json; charset=UTF-8',
    'Authorization': 'Bearer <access_token>
}

But the server returns:

<Response [401]>
{
  "error": {
    "errors": [
      {
        "domain": "global",
        "reason": "authError",
        "message": "Domain cannot use Api, Groups service is not installed.",
        "locationType": "header",
        "location": "Authorization"
      }
    ],
    "code": 401,
    "message": "Domain cannot use Api, Groups service is not installed."
  }
}

even though I have groups enabled and I can use this service from admin console. (Directory API, however, does work)
When I created a new dummy account for testing, everything worked seamlessly.
How can I fix this problem and use API with my old account?

Answer 1

In order to use Groups Settings API, you need to have Groups for Business turned on.