Magento – The requested Payment Method is not available When creating an order

We get The requested Payment Method is not available error when we try to create order using REST api.payment method works fine with all online orders and i am using given api.

Request- (Put)

http://MyHost.com/rest/V1/carts/67/order 
json-{ "paymentMethod": { "method": "free"}}

Response-

{
  "message": "The requested Payment Method is not available.",
  "trace": "#0 /chroot/home/folder/html/vendor/magento/module-quote/Model/QuoteManagement.php(337): Magento\\Quote\\Model\\Quote\\Payment->importData(Object(Magento\\Framework\\DataObject))\n#1 [internal function]: Magento\\Quote\\Model\\QuoteManagement->placeOrder(67, Object(Magento\\Quote\\Model\\Quote\\Payment))\n#2 /chroot/home/folder/html/vendor/magento/module-webapi/Controller/Rest.php(307): call_user_func_array(Array, Array)\n#3 /chroot/home/folder/html/vendor/magento/module-webapi/Controller/Rest.php(216): Magento\\Webapi\\Controller\\Rest->processApiRequest()\n#4 /chroot/home/folder/html/var/generation/Magento/Webapi/Controller/Rest/Interceptor.php(37): Magento\\Webapi\\Controller\\Rest->dispatch(Object(Magento\\Framework\\App\\Request\\Http))\n#5 /chroot/home/folder/html/vendor/magento/framework/App/Http.php(135): Magento\\Webapi\\Controller\\Rest\\Interceptor->dispatch(Object(Magento\\Framework\\App\\Request\\Http))\n#6 /chroot/home/folder/html/vendor/magento/framework/App/Bootstrap.php(258): Magento\\Framework\\App\\Http->launch()\n#7 /chroot/home/folder/html/index.php(39): Magento\\Framework\\App\\Bootstrap->run(Object(Magento\\Framework\\App\\Http))\n#8 {main}"
}

Did I miss something About setting ?

and i am using following steps to create an order.

Create customer-

curl -g -X POST "$base_url/index.php/rest/V1/customer" \ -H "Authorization: Bearer $token" \ -H "Content-Type:application/json" \ -d '{"customer":{"email":"sunny.kumar@web.biz","firstname":"sunny","lastname":"kumar","store_id":1,"website_id":1,"addresses":[{"region":{"region_code":"WA","region":"Washington","region_id":62},"region_id":62,"country_id":"US","street":["1401 Pennsylvania Ave NW, Washington"],"telephone":"1 202-628-9100","postcode":"DC 20004","city":"Washington","firstname":"sunny","lastname":"kumar","prefix":"Mr."},{"region":{"region_code":"WA","region":"Washington","region_id":62},"region_id":62,"country_id":"US","street":["1401 Pennsylvania Ave NW, Washington"],"telephone":"1 202-628-9100","postcode":"DC 20004","city":"Washington","firstname":"sunny","lastname":"kumar","prefix":"Mr.","default_shipping":true,"default_billing":true}],"disable_auto_group_change":0}}'

Create cart-

Creates an empty cart and quote for a specified customer.

curl -g -X POST "$base_url/index.php/rest/V1/customer/{customerId}/carts/" \ -H "Authorization: Bearer $token"

Add Product To Cart

curl -g -X POST "$base_url/index.php/rest/V1/carts/67/items" \ -H "Authorization: Bearer $token" \ -H "Content-Type:application/json" \ -d '{ "cartItem": { "quote_id": "67", "sku": "Test-Sku", "qty": 2 } }'

Get Payment Method

curl -g -X GET "$base_url/index.php/rest/V1/carts/67/payment-information" \ -H "Authorization: Bearer $token"

response-
[
{
"code": "free",
"title": "No Payment Information Required"
}
]

Place Order

curl -g -X PUT "$base_url/index.php/rest/V1/carts/67/order" \ -H "Authorization: Bearer $token" \ -H "Content-Type:application/json" \ -d ' { "method": { "method": "free" } } '