@geetha.gubendran: as a side note you can use 3 back ticks to format code in here, like so (your code in essence):

<http://Fuel.post|Fuel.post>(Utils.getRootURL() + "/user", listOf(...) .response {
    request, response, either ->
    when (either) {
        is Either.Left -> {
            Log.d(TAG, "Error String")
        }
        is Either.Right -> {
            Log.d(TAG, response.toString())
        }
    }
}