Could not load type "App\Form\Type": class does not exist.

Je n'arrive pas a afficher le formulaire d'ajouter d'un nouveau Dossier

#[Route('/dossier/new', name: 'dossier_new', methods: ['GET', 'POST'])]
public function new(Request $request, Security $security): Response
{
    if (!$this->isGranted('IS_AUTHENTICATED_FULLY')) {
        return $this->redirectToRoute('fos_user_security_login');
    }

    $dossier = new Dossier();
    $demandeur = new Demandeur();
    $piecejointe = new PiecesJointe();

    //$form = $this->createForm(DossierType::class, $dossier);
    //$formDemand = $this->createForm(DemandeurType::class, $demandeur);
    //$formPJ = $this->createForm(PiecesJointeType::class, $piecejointe);

    $form = $this->createForm(DossierType::class, $dossier);
    $formDemand = $this->createForm(DemandeurType::class, $demandeur);
    $formPJ = $this->createForm(PiecesJointeType::class, $piecejointe);

    $form->handleRequest($request);
    $formDemand->handleRequest($request);
    $formPJ->handleRequest($request);

    if ($form->isSubmitted() && $form->isValid()) {
        $em = $this->getDoctrine()->getManager();

        $dossier->setNumeroDossier($em->getRepository(Dossier::class)->getNumeroDispo());

        $id_d = $dossier->getDemandeur();
        if ($id_d === null) {
            $em->persist($demandeur);
            $em->flush();
            $dossier->setDemandeur($demandeur);
        } else {
            $dossier->setDemandeur($id_d);
        }

        $dossier->setDateEnregistrement(new \DateTime());
        $dossier->setSupp(false);
        $em->persist($dossier);
        $em->flush();

        $dossier->upload();
        $dossier->upload2();

        $session = $request->getSession();
        $session->set('dossier', $dossier);

        // Redirect or handle success
        return $this->redirectToRoute('page_accueil'); // Replace with your success route
    }

    // Render form view or return response
    return $this->render('dossier/new.html.twig', [
        'form' => $form->createView(),
        'formDemand' => $formDemand->createView(),
        'formPJ' => $formPJ->createView(),
    ]);
}

Ce que je veux
Enregistrer un nouveau Dossier

Ce que j'obtiens

Could not load type "App\Form\Type": class does not exist.