Getting "Unauthorized' when calling API with a valid token

Hello friends,

We are new to Gainsight Digital Hub. I’m working on a script to migrate posts from a Zendesk forum to a category in Gainsight. I am able to retrieve a token with read write scope, but when I call the POST /conversations endpoint, I’m getting an Unauthorized response. I’ve tried with and without moderatorId and with and without authorId, and with just one or the other. 

I then decided to just try to list categories and get the same result. 

For completeness, here’s the code (in it’s current configuration):

 

def gdh_auth():

    headers = {
        "Content-Type": "application/x-www-form-urlencoded"
    }

    body = {
        "grant_type": "client_credentials",
        "client_id": client_id,
        "client_secret": client_secret,
        "scope": "write read"
    }

    response = requests.post("https://api2-us-west-2.insided.com/oauth2/token", data=body, headers=headers)

    auth_json = response.json()

    return auth_json['access_token']

def list_categories():
    url = "https://api2-eu-west-1.insided.com/v2/categories?authorId=505"

    headers = {
        "Authorization": f"Bearer {auth_code}",
        "Content-Type": "application/json"
    }

    response = requests.request(
        "GET",
        url,
        headers=headers
    )

    print(f"categories list {response.text}")

def create_post(post):
    url = "https://api2-eu-west-1.insided.com/v2/conversations/start?authorId=505&moderatorId=505"

    headers = {
        "Authorization": f"Bearer {auth_code}"
    }

    payload = {
        "title": post['title'],
        "content": post['details'],
        "categoryId": 24,
        "tags": [
            "developer",
            "archive"
        ],
        "sticky": False,
        "closed": True
    }

    print(f"headers {headers}")
    print(f"payload: {payload}")

    response = requests.post(url, data=payload, headers=headers)

    print(f"response.headers: {response.headers}")
    print(f"response body: {response.text}")

No matter what, I receive the following:
 

response.headers: {'Date': 'Fri, 15 Mar 2024 13:27:34 GMT', 'Content-Type': 'application/json; charset=utf-8', 'Content-Length': '26', 'Connection': 'keep-alive', 'Server': 'openresty', 'WWW-Authenticate': 'Key realm="kong"'}

response body: {"message":"Unauthorized"}

user 505 is an admin, if that matters. 

Any pointers would be greatly appreciated.