the twitch kraken API has been decommissioned and replaced by the helix API. Using the actual auth provider will result in an error asking to upgrade to new API. The actual auth provider is not able to retrieve oauth token neither user information. URLs has changed and users REST endpoint has changed.
The two following patches have fixed the issue on my local install but I'm not sure that the return statement is the arcanist.diff is correct (I'm not a PHP dev)