Was the order rejected with status code 400? You will receive an order postback only for 200 status order placement. You can know more about this here.
You seem to have not set any postback URL on the developers console. You need to enter a valid https url so that kite trade can send you the data using a post request.
You will receive an order postback only for 200 status order placement. You can know more about this here.
sample order- 210312203754599 , 210312203754689