PHP Session not setting - php

Question

I have a PHP page and session, i started session on top of every site, but this isn't working.
I'm setting session (I'm setting class into session) with
}else if(isset($_POST['username']) and isset($_POST['password'])){
$account = new Account;
$password = hash('sha256', $_POST['password']);
$account->setTheAccount($_POST['username'],$password);
$acc_data = $account->getDatabaseAccounts('root','','schoolpage','localhost','accounts');
$acc_status = $account->isAccountTrue();
if ($acc_status==true){
$_SESSION['account'] = $account;
echo 'true';
header('Location:panel.php');
}else{
echo 'false';
}
}
and accessing it by:
if (isset($_SESSION['account'])){
$account = $_SESSION['account'];
if ($account->isAccountTrue() == true){
echo 'XD';
}
}
but it doesnt work.
I haven't idea why session not working.
Account class
class Account{
private $acc_data,$username,$password;
function setTheAccount($usernamei, $passwordi){
$this->username = $usernamei;
$this->password = $passwordi;
}
function getDatabaseAccounts($dbUser,$dbPassword,$dbName,$dbHost, $dbTable){
$pdo = new PDO('mysql:host='.$dbHost.';dbname='.$dbName, $dbUser, $dbPassword);
$this->acc_data = $pdo->query('SELECT * FROM `'.$dbTable.'`');
}
function isAccountTrue(){
$acc_status=false;
foreach ($this->acc_data as $i) {
if ($i['username'] == $this->username and $i['password'] == $this->password){
$acc_status = true;
}
}
return $acc_status;
}
function isUserLogged(){
}
}
Account class var dump
truearray(2) { ["login"]=> bool(true) ["account"]=> object(Account)#1 (3) { ["acc_data":"Account":private]=> object(PDOStatement)#3 (1) { ["queryString"]=> string(24) "SELECT * FROM `accounts`" } ["username":"Account":private]=> string(5) "admin" ["password":"Account":private]=> string(64) "4813494d137e1631bba301d5acab6e7bb7aa74ce1185d456565ef51d737677b2" } }

Answer 1

To store an object in $_SESSION you have to serialize it, then deserialize it to call the method ->isAccountTrue(), otherwise just store the result:
$_SESSION['accountValid']=$account->isAccountTrue();
...
if($_SESSION['accountValid']===true){
// do stuff
}

Answer 2

Put
error_reporting(-1);
ini_set('display_errors', true);
on top of the page to enable the php errors, and you will see that you can't serialize a resource, PDO instances, PDOStatement, etc. into session.
You can't serialize Account's $acc_data, since it's an instance of PDOStatement. You cannot serialize or unserialize PDOStatement instances.
Change
$this->acc_data = $pdo->query('SELECT * FROM `'.$dbTable.'`');
to
$this->acc_data = $pdo->query('SELECT * FROM `'.$dbTable.'`')->fetchAll();
then delete your session and retry.