I can't reach customers AdWords Account with Google Login - google-ads-api

Question

I want to connect -any- customer Google AdWords Account with Google Login. (Like Wordstream)
I prepared a code, but there is a problem somewhere, I can't run it.
When the customer press the connect button, the screen appears. It says "XXX wants to acces your Google Account", it is approved but I cannot receive data.
How can i get datas from customer's account?
Code:
require 'google-api/vendor/autoload.php';
use Google\Auth\OAuth2;
use Google\AdsApi\AdWords\AdWordsServices;
use Google\AdsApi\AdWords\AdWordsSessionBuilder;
use Google\AdsApi\AdWords\v201809\cm\CampaignService;
use Google\AdsApi\Common\OAuth2TokenBuilder;
session_start();
$oauth2 = new OAuth2([
'authorizationUri' => 'https://accounts.google.com/o/oauth2/v2/auth',
'tokenCredentialUri' => 'https://www.googleapis.com/oauth2/v4/token',
'redirectUri' => 'https://xxxxx.xxxxxx',
'clientId' => 'xxxxxxxxx.apps.googleusercontent.com',
'clientSecret' => 'xxxxxxxxxxx',
'scope' => 'https://www.googleapis.com/auth/adwords',
'refresh_token' => 'xxxxxxxxxx'
]);
if(!isset($_GET['code'])){
$oauth2->setState(sha1(openssl_random_pseudo_bytes(1024)));
$_SESSION['oauth2state'] = $oauth2->getState();
$config = [
'access_type' => 'offline',
'prompt' => 'consent',
];
header('Location: ' . $oauth2->buildFullAuthorizationUri($config));
exit;
} elseif (empty($_GET['state']) || ($_GET['state'] !== $_SESSION['oauth2state'])){
unset($_SESSION['oauth2state']);
exit('Invalid state.');
} else {
$oauth2->setCode($_GET['code']);
$authToken = $oauth2->fetchAuthToken();
$refreshToken = $authToken['refresh_token'];
$path = "xxxxx/google-api/vendor/adsapi_php.ini";
$session = (new AdWordsSessionBuilder())
->fromFile($path)
->withOAuth2Credential($oauth2)
->build();
$adWordsServices = new AdWordsServices();
$campaignService = $adWordsServices->get($session, CampaignService::class);
print_r($campaignService);
}