The class 'fuar\sergiBundle\Entity\Product' was not found in the chain configured namespaces error

Mongodb is runnig . I don't understand what is the problem. Please help me!

app/config.yml

doctrine_mongodb:

    connections:

        default:

            server: mongodb://localhost:27017

            options: {}

    default_database: test_database

    document_managers:

        default:

            auto_mapping: true

Controller

namespace fuar\sergiBundle\Controller;

use fuar\sergiBundle\Entity\Product;

use Symfony\Bundle\FrameworkBundle\Controller\Controller;

use Symfony\Component\HttpFoundation\Response;

class DefaultController extends Controller

{

    public function indexAction()

    {

        $product = new Product();

        $product->setName("xxx");

        $product->setAge('25');

        $product->setSchool("xxxx");

        

        $dm = $this->get('doctrine_mongodb')->getManager();

        $dm->persist($product);

        $dm->flush();

        

         return new Response('Created product id '.$product->getId());

    }

}

fuar/sergiBundle/Entity/Product.php

namespace fuar\sergiBundle\Entity;

use Doctrine\ODM\MongoDB\Mapping\Annotations as MongoDB;

/**

 * Product

 */

class Product

{

    /**

     * @var integer

     */

    private $id;

    /**

     * @var string

     */

    private $name;

Cross-referencing this with: https://github.com/doctrine/DoctrineMongoDBBundle/issues/275, which has been answered.