Symfony doctrine is not doing create / update / delete

  crud, doctrine, symfony

I was working on a symfony project last month, I could CRUD data with my entities.
But now, I can’t create, update or delete a data.
I can only read data, everything is fine to read it.

When I submit a form, no error is displayed.

I tried to submit a form to create an idea. No idea is created. But when I tried to return the data json when I submit my form, the date is good, but no changes in my database.

I don’t know since when I have this problem, all these forms worked a few weeks ago.

Does anyone know why ?

Example of a route :

     * @Route("/{projet}/{id_projet}/idee/nouvelle",name="projet_idee_nouvelle")
    public function projet_idee_nouvelle(int $id_projet,Request $request, ObjectManager $manager){
        $idee=new Idee();

        $repository = $this


        $form=$this->createForm(IdeeType::class,$idee, array(


        if($form->isSubmitted() && $form->isValid()){

            //redirection on the created project
            return $this->redirectToRoute('projet_detail',array('id'=>$projet->getId()));

        return $this->render('idee/idee_nouveau.html.twig',[

Source: Symfony Questions