Oauth token, return 401 error

API
2

After doing the authorize call, you are returned to your server.

You must then take the code passed and exchange to code for a token.

Then you must use the token as OAuth in the requests.

Further more your PHP is wrong try this:

curl_setopt($ch, CURLOPT_HTTPHEADER, array(
    'Authorization: OAuth '.$code,
    ‘Accept: application/vnd.twitchtv.v5+json’,
    ‘Content-Type: application/json’,
    'Client-ID: '.$clientid
));

You were only setting ONE header containing the clientID. The first three are overwritten