Google API中的令牌格式无效

there i found some error, when i want to make sure the session on Login with google account. And the error is :

Fatal error: Uncaught InvalidArgumentException: Invalid token format in C:\xampp\htdocs\google\googleAPI\src\Google\Client.php:434 Stack trace: #0 C:\xampp\htdocs\google\callback.php(5): Google_Client->setAccessToken(Array) #1 {main} thrown in C:\xampp\htdocs\google\googleAPI\src\Google\Client.php on line 434

and then this is my code :

<?php   
require_once('config.php');

if (isset($_SESSION['accessToken'])){
    $client->setAccessToken($_SESSION['accessToken']);
}
else if (isset($_GET['code'])) {
    $token = $client->fetchAccessTokenWithAuthCode($_GET['code']);
    $_SESSION['accessToken'] = $token;


}
else{
    header("location: index.php");
}

$oAtuth = new Google_Service_Oauth2($client);
$user = $oAtuth->userinfo->get();

echo "<pre>";

print_r($user);

?>

Please tell me whats wrong with this code

You have wrong value of token in $_SESSION['accessToken'].