PARDOT API ERROR: "access_token is invalid, unknown, or malformed: Invalid scope"

- We checked  access token is formatted correctly and was obtained using a Connected App that includes the pardot_api OAuth scope

- Also checked the user associated with the token is synced to the Pardot business unit

- We also check the token used is within its expiration time.

But we still keep getting this error in Postman:

{

    "@attributes": {

        "stat": "fail",

        "version": 1,

        "err_code": 184

    },

    "err": "access_token is invalid, unknown, or malformed: Invalid scope"

}

And we also have a Python script that gives us the same issue and at one point it used to work - what is something we are not accounting for:

# auth headers
auth_header = {
    'Pardot-Business-Unit-Id': pardot_business_unit_id,
    'Authorization': f"Bearer {access_token}"
    }
try:
        pardot_request = r.get(
            url= f"https://pi.pardot.com/api/{object_name}/version/4/do/query?format=json",
            headers = {
                'Pardot-Business-Unit-Id': pardot_business_unit_id, 
                'Authorization': f"Bearer {access_token}"
                }
        )
        # Convert JSON string to JSON object
        json_object = json.loads(pardot_request.text)
        print(json_object)
        data_dict = json_object['result'][object_name]
        df = pd.DataFrame(data_dict)
        print(df.shape)
        return df
    except Exception as e:
        print(e.trace)