Hey, @rjayaram glad to know you were able to develop an alternative solution. 
Error socket hang up error received in client pretty much always indicates the server closed the connection for various reason (not being able to process the request in time, or running into some error while processing the request, etc).
I’m just wondering if the library you are using isn’t sending requests asynchronously as pm.sendRequest() does?
I would love to find out why your Python script works for you while newman fails! Which library/methods you are using to send requests in Python? An example script would help us improve solutions at our end 
Thank you! 