webSocket with Symfony : why the webSocket only intercept the first connection?

Question

this is he onOpen() function :

private $clients;

        public function __construct()
        {
            $this->clients = new SplObjectStorage();
            
        }
        
     
        public function onOpen(ConnectionInterface $conn)
        {

            $cookie = $myCookieValue = $conn->httpRequest->getHeaders()['Cookie'][0];
            $sessionid = explode('=', $cookie)[1];
            
            session_id($sessionid);
            session_start();
            $data = $_SESSION;
            session_write_close();
            $email = $data["_sf2_attributes"]['email'];
            $id = $data["_sf2_attributes"]['id'];
            // Store client data in SplObjectStorage
            $this->clients->attach($conn, [
                'id' => $id,
                'email' => $email,
            ]);

            echo "New connection: " . $conn->resourceId . " there is ". sizeof($this->clients) ." client\n";
        }

i want to make a private chat application with symfony but the problem is that when i make 2 connection to this webSocket server it only detect the first client this is the output: New connection: 566 there is 1 client also when i send msg with the second client the server intercept the msg i want to know why only the first client is stored in the array "$this->clients"