microsoft Graph API for subscription throwing wrong message and not creating subscription

I am using Microsoft graph API and trying to create a subscription on the Microsoft developer portal.

https://graph.microsoft.com/v1.0/subscriptions I am hitting this URL with post request call as shown below

`

import requests

access_token = "testtoken"
subscription_data = {
    "changeType": "created,updated",
    "notificationUrl": "WEBHOOK URL",
    "resource": "me/contacts",
    "expirationDateTime": '2023-01-16T16:58:00.0000000Z'
}

headers = {
    'Authorization': 'Bearer ' + access_token,
    'Content-Type': 'application/xml'
}
try:
    response = requests.post(f'https://graph.microsoft.com/v1.0/subscriptions', json=subscription_data, headers=headers)
except Exception as e:
    print("error")

Above code is giving wrong message response as

 `{
        "error": {
            "code": "InvalidRequest",
            "message": "Could not process subscription creation payload. Are all property names spelled and camelCased properly?Also are the dateTimeOffest properties in a valid internet Date and Time format?",
            "innerError": {
                "date": "2023-01-14T19:09:17",
                "request-id": "6d50105e-08b1-494d-8400-5fc32909a8d1",
                "client-request-id": "c89e988f-783b-daf5-7d95-677002b0c22d"
            }
        }
    }
    `

As you see all property are in camelcase and date format is also in 8601 iso format, still getting errors and not able to create a subscription . I also saw similar problem faced and discussed here https://github.com/microsoftgraph/microsoft-graph-docs/issues/3041 however this is also not giving explanations how to solve the problem