How to fix The page isn’t redirecting properly

Question

I am trying to login with google api for php and then redirect the user to the dashboard.php but suddenly this error occurred during the redirection my files: the callback file that is responsible for tokens and redirection to dashboard.php

<?php
session_start();
require_once("../gog.php");
 
    if (isset($_SESSION['access_token']))
        $gClient->setAccessToken($_SESSION['access_token']);
    else if (isset($_GET['code'])) {
        $token = $gClient->fetchAccessTokenWithAuthCode($_GET['code']);
        $_SESSION['access_token'] = $token;
    } else {
        header('Location:../index.php');
        exit();
    }

    $oAuth = new Google_Service_Oauth2($gClient);
    $userData = $oAuth->userinfo_v2_me->get();



    header('Location:../client/dashboard.php');
        exit();


?>

the gog.php which includes the settings (i deleted the values)

<?php
    require_once "vendor/autoload.php";
    $gClient = new Google_Client();
    $gClient->setClientId("");
    $gClient->setClientSecret("");
    $gClient->setApplicationName("");
    $gClient->setRedirectUri("");
    $gClient->addScope("");
    $loginURL = $gClient->createAuthUrl();


?>

the index php where it testes wether or not the user is signed in with google account or email pwd

<?php
require_once("includes/config.php");
require_once("gog.php");
require_once("includes/classes/Account.php");


$account=new Account($con);
if(isset($_SESSION["clientLoggedIn"]) || isset($_SESSION['access_token']) ){
    header('location:client/dashboard.php');
    exit();
}
?>

the config.php file included which has the database setting to connect

<?php

ob_start();
session_start();


try{
    $con= new PDO("mysql:dbname=cinecad;host=localhost","root","");
    $con->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_WARNING);

}catch(PDOException $e){
    exit("Connexion failed:".$e->getMessage());
}

?>

and the finally the dashbaord.php

<?php
session_start();

if(!isset($_SESSION["clientLoggedIn"])||!isset($_SESSION['access_token'])){

    header("Location:../index.php");
}



?>

Answer 1

Based on @Alon Eitan comment the answer was $_SESSION["clientLoggedIn"] = true