Cannot autowire service "App\Controller...

Bonjour! Je suis entrain de suivre la formation de GrafiKart concernant Symfony. Je suis bloqué quelque part quand j'essai de récupérer les donnes. Voici le message d'erreur:

Cannot autowire service "App\Controller\PropertyController": argument "$em" of method "__construct()" references interface "Doctrine\Persistence\ObjectManager" but no such service exists. You should maybe alias this interface to the existing "doctrine.orm.default_entity_manager" service.

Mon controller

<?php
namespace App\Controller;
use App\Entity\Property;
use App\Repository\PropertyRepository;
use Doctrine\Persistence\ObjectManager;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\Routing\Annotation\Route;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;

class PropertyController extends AbstractController
{
    /**
     * @var PropertyRepository
     */
    private $repository;
    /**
     * @var ObjectManager
     */

    public function __construct(PropertyRepository $repository, ObjectManager $em)
    {
        $this->repository = $repository;
        $this->em = $em;
    }

    /**
     * @Route("/biens", name="property.index")
     * @return Response
     */
    public function index():Response
    {
        /*insersion des données dans la base via le controller.
            $property = new Property();
            $property->setTitle('Mon premier bien')
                ->setPrice(4000)
                ->setRooms(4)
                ->setBedrooms(3)
                ->setDescription('Une pièce que nous avons')
                ->setSurface(60)
                ->setFloor(4)
                ->setHeat(1)
                ->setCity('Lubumbashi')
                ->setAddress('16/Munongo/Maman YEMO/Mont-Ngafula')
                ->setPostalCode('34000');

                $em = $this->getDoctrine()->getManager();
                $em->persist($property);
                $em->flush();   
        */
        $repository = $this->repository->findAllVisible();
       $repository[0]->setSold(true);

        $this->em->flush();
        return $this->render('property/index.html.twig', [
            'current_menu' => 'properties'
        ]); 
    }
}

Ce que je veux

Que ce problème soit résolu

Ce que j'obtiens
Message d'erreur