youtube caption download using youtube v3 api

I used GET https://www.googleapis.com/youtube/v3/captions api to get the captions list which returns like this

{"kind": "youtube#captionListResponse","etag": "V4ixyY6VwcMboAfZRMkg5UA4trM","items": [    {"kind": "youtube#caption","etag": "4Uk_V50p_bLjKsPKh9KN2SNnSS8","id": "AUieDaaDF0pplLiwXqJ0-intXtS-3LwTRsMjwu7HFSrs02wNGjM"    }  ]}

then I want to download the captions using the GET https://www.googleapis.com/youtube/v3/captions/AUieDaaDF0pplLiwXqJ0-intXtS-3LwTRsMjwu7HFSrs02wNGjM

but i get 404 not found.. how to download the caption for any youtube video.. is the above process is incorrect? the video is not owned by me .. does the owner has to give permission to download transcript?