I am attempting to Add a CancelOrderUsingOrderNumber API Method which only returns an OK(200) Status and a Text Message as to whether It's Successfully Canceled the Order or Not. Oddly, I receive an Object Reference Not Found Error on Send. Are you expecting a JSON Response Object and not just an HTTP Status with a single Message? Might this be the cause of said error? If so, I suppose that I could create a Generic JSON Message Object to return if hit would help.