The documentation for v5 doesn’t offer the ability to pass an oAuth_token via query string.
You also declared no accept version which reverts to v3 rather that v5
Should be calling it via:
For example
curl -H 'Accept: application/vnd.twitchtv.v5+json' \
-H 'Client-ID: uo6dggojyb8d6soh92zknwmi5ej1q2' \
-H 'Authorization: OAuth cfabdegwdoklmawdzdo98xt2fo512y' \
-X GET 'https://api.twitch.tv/kraken/user'
Please bear in mind that visiting the URL in your browser, currently appears to use your Twitch Logged in Website cookies to perform the request so it will work regardless…