Adding members to google group in python

Question

I am trying to add members to google group using the python script as shown below. I am using a service account to add members to a group. However, I am getting the below error:

Error:

An error occurred: ('unauthorized_client: Client is unauthorized to retrieve access tokens using this method, or client not authorized for any of the scopes requested.', {'error': 'unauthorized_client', 'error_description': 'Client is unauthorized to retrieve access tokens using this method, or client not authorized for any of the scopes requested.'})

python script:

from google.oauth2 import service_account
from pathlib import Path
from googleapiclient.discovery import build
import os
BASE_DIR = Path(__file__).resolve().parent
CREDENTIAL_PATH = os.path.join(BASE_DIR, "python-demo-project-service-account.json")

print(CREDENTIAL_PATH)

# Path to your service account key file
SERVICE_ACCOUNT_FILE = CREDENTIAL_PATH

# The email of the Google Group to modify
GROUP_EMAIL = 'email.com'

# The email of the user to add to the group
USER_EMAIL = '[email protected]'

# Scopes required for the Directory API
SCOPES = ['https://www.googleapis.com/auth/admin.directory.group.member']

def add_user_to_group(service_account_file, group_email, user_email):
    credentials = service_account.Credentials.from_service_account_file(
        service_account_file, scopes=SCOPES)

    # You need to specify the subject email if you're using domain-wide delegation
    # This is the email of a user in the domain with sufficient permissions to add members to a group
    delegated_credentials = credentials.with_subject('[email protected]')

    service = build('admin', 'directory_v1', credentials=delegated_credentials)

    member = {
        'email': user_email,
        'role': 'MEMBER'
    }

    try:
        result = service.members().insert(groupKey=group_email, body=member).execute()
        print(f'Added {user_email} to {group_email}: {result}')
    except Exception as e:
        print(f'An error occurred: {e}')

# Add a user to the group
add_user_to_group(SERVICE_ACCOUNT_FILE, GROUP_EMAIL, USER_EMAIL)

Can someone help me what permissions my service accounts needs or am I missing something.