Getting error_code 5 for some tracks.

I am using echonest API to create dynamic playlist. When i fire following request from device it gives code = 5. But if i fire same request from browser it give message = "success". Can anyone please tell why response different on device than browser.

Request-

http://developer.echonest.com/api/v4/playlist/dynamic/create?api_key=TAFYO7QHYKWQE791F&artist=Nakash%20Aziz,Ritu%20Pathak&song_id=spotify-WW:track:1At6Fbe8RxXE6tKKJtMbyW&bucket=id:spotify-WW&limit=true&type=artist-radio&adventurousness=1

Response on device

{ status = { code = 5; message = "The Identifier specified does not exist"; version = "4.2"; }; };