How to get shipping methods in place order in magento 2 using REST API?

Hi i am udhay new to this magento i have trying to place order from my android app i have followed this link (https://stackoverflow.com/questions/33770986/how-to-place-an-order-using-magento2-api) to create empty cart, add item in cart, add billing address, get shipping methods, add shipping info, place order..
But i have stucked in get shipping methods and add shipping info

Shipping methods :
shows result= [](only empty array)..

estimate-Shipping-methods-addressById :
shows result= [](only empty array)..

Shipping info :
shows result=

{"message":"Carrier with such method not found: %1, %2","parameters":["freeshipping","freeshipping"],"trace":"#0 [internal function]: Magento\Checkout\Model\ShippingInformationManagement->saveAddressInformation(408, Object(Magento\Checkout\Model\ShippingInformation))n#1 /var/www/vendor/magento/module-webapi/Controller/Rest.php(307): call_user_func_array(Array, Array)n#2 /var/www/vendor/magento/module-webapi/Controller/Rest.php(216): Magento\Webapi\Controller\Rest->processApiRequest()n#3 /var/www/var/generation/Magento/Webapi/Controller/Rest/Interceptor.php(37): Magento\Webapi\Controller\Rest->dispatch(Object(Magento\Framework\App\Request\Http))n#4 /var/www/vendor/magento/framework/App/Http.php(135): Magento\Webapi\Controller\Rest\Interceptor->dispatch(Object(Magento\Framework\App\Request\Http))n#5 /var/www/vendor/magento/framework/App/Bootstrap.php(258): Magento\Framework\App\Http->launch()n#6 /var/www/index.php(39): Magento\Framework\App\Bootstrap->run(Object(Magento\Framework\App\Http))n#7 {main}"}

my payment info :
shows result = Payment methods successfully

My API URL is:

$base_url.’index.php/rest/V1/carts/mine/estimate-shipping-methods-by-address-id’

All topic

Magento 2.1. How to display select box instead of box in checkout shipping address?

As checkout page layout is mostly build in knockout.js and I have zero knowledge of knockout.js.

I want to show shipping address in select box