Login addon: manager access problem

$userObject = $hook->getValue('login.user');

$userName = $hook->getValue('username');

$userName = $hook->getValue('login.username');

$userObject = $hook->getValue('login.user');
// Output: NULL
$userName = $hook->getValue('username');
// Output: String(11) "asampleuser"  
$userName = $hook->getValue('login.username');
// Output: NULL

$user = $hook->modx->user;
$whitelistUserGroups = array("Team Management");
var_dump($user->isMember($whitelistUserGroups));
exit();
// Output: bool(true)

$currentUser = $modx->getObject('modUser', array('username' => $userName));

var_dump($hook->getValue('user'));
// Output: NULL

<?php
// A whitelist of User Groups which may login at frontend.
$whitelistUserGroups = array("Team Management");

// Only check user at login, not logout
if ($hook->getValue('service') === "login") {
    // Retrieve user
    $userName = $hook->getValue('username');
    $currentUser = $modx->getObject('modUser', array('username' => $userName));
    
    // Check if user has access to any available user group 
    if ($currentUser && $currentUser->isMember($whitelistUserGroups) === false) {
        // The user has manager access, but no access to
        // any protected resources over here, send them 
        // to the manager
        $modx->sendRedirect($modx->getOption("site_url") . '/manager');
    }
}

return true;