HTTP 400 Bad Request while creating a session - EMC Isilon

One issue was encountered while making a POST call to Isilon endpoint as shown in the python script in the attached image

Request Parameters - {"username":"abc", "password":"xyz", "services":["namespace","platform"]}

Request Headers - Content-Type = application/json

The response from the python script is given below:

Response text -

400 Bad Request

Bad Request

Your browser sent a request that this server could not understand.

Additionally, a 400 Bad Request

error was encountered while trying to use an ErrorDocument to handle the request.

Response Status Code - 400

Response Cookies - {}

What can be the reason behind the blank cookies in the above response?

Script to fetch cookies from session