adldap2为搜索查询返回null

I'm trying to move my php code to adldap2 because it's supposed to be easier, but i'm having issues searching for users in groups. Basically, what i'm trying to accomplish is...if user is in group, authenticate.

I've broken down the code to just trying to search for users in AD, but for some reason it's returning

object(Adldap\Query\Collection)#17 (1) { ["items":protected]=> array(0) { } }

<?php

    include "includes/functions.inc.php";
    require __DIR__ . '/vendor/autoload.php';
    $ad = new \Adldap\Adldap();

// Create a configuration array.
$config = [  
  // An array of your LDAP hosts. You can use either
  // the host name or the IP address of your host.
  'hosts'    => ['ad.test.local'],

  // The base distinguished name of your domain to perform searches upon.
  'base_dn'  => 'dc=test,dc=local',

  // The account to use for querying / modifying LDAP records. This
  // does not need to be an admin account. This can also
  // be a full distinguished name of the user account.
  'username' => 'USERNAME',
  'password' => 'PASSWORD',
];

$ad->addProvider($config);

try {
    // If a successful connection is made to your server, the provider will be returned.
$provider = $ad->connect();

$search = $provider->search();


$query = $provider->search()->newQuery();

$results = $query->andFilter(function (Adldap\Query\Builder $q) {

    $q->where('samaccountname', '=', 'USER')
        ->where('memberof', '=', 'testgroup');

})->get();

var_dump($results);

} catch (\Adldap\Auth\BindException $e) {

    echo "Issue with LDAP";

}

?>