Using the Google Developer Api Tool I have been able to execute a blank query and return a list of contact groups, exactly as expected. When using the same cURL request from my PHP app I don't get anything but some system contact groups (and not all overlap with the tool's response). I can't figure out why this would be the case, am I missing something really obvious?

The Curl Request c&p'd from the google developer tool:

    curl \
  'https://people.googleapis.com/v1/contactGroups?key=[YOUR_API_KEY]' \
  --header 'Authorization: Bearer [YOUR_ACCESS_TOKEN]' \
  --header 'Accept: application/json' \
  --compressed

And my php cURL request:

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "https://people.googleapis.com/v1/contactGroups");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'GET');

$headers = ["Authorization: Bearer {$access_token}", "Accept: application/json"];
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
$data = curl_exec($ch);
$result = json_decode($data, true);
var_dump($result); die();

The returned outputs of the requests are in the same format, just the content differs. Does anyone have experience trying to get a list of contact groups/labels from the people api?