With that simple PHP script you’re not bringing in your authenticated session. Add at the top before you include /etc/freepbx.conf:
// this is from config.php
if (!isset($_SESSION)) {
//start a session if we need one
$ss = @session_start();
if(!$ss){
session_regenerate_id(true); // replace the Session ID
session_start();
}
}
Or bypass auth altogether with:
$bootstrap_settings['freepbx_auth'] = false;
before requiring /etc/freepbx.conf. But of course, disclaimer: bypass security at your own peril.