Getting boolean false from Twitch Authentication

API
4

Your code tests fine for me.

I ran

$tw = new TwitchApi('ValidClientID', 'ValidSecret', 'RedirectForThisClient');
$r = $tw->get_tokens('A Code');

print_r($r);

And was returned

{"access_token":"REDACTED","refresh_token":"REDACTED","token_type":"bearer"}

Note: no expires_in as it was a legacy clientID tested with

Under PHP 7.2.24 on the machine tested on