错误：Zend \ ServiceManager \ Exception \ ServiceNotCreatedException

I try to create a module Users I am inspire from the Blog Exemple of zend 2.4, I build a factory to instantiate my controller UsersController, but i get this error:

An exception was raised while creating "Users\Controller\Users"; no instance returned

Actually the problem arise when I bring the service into the controler

class UsersController extends AbstractActionController {

    protected $userService;

    public function __construct(UserServiceInterface $userService){
        $this->userService = $userService ;
    }
}

Then I defined UserServiceInterface and create an instance of the 'Users\Controller\UserController' and change the configuration:

'controllers' => array(
    'factories' => array(
         'Users\Controller\Users' => 'Users\Factory\UserControllerFactory'
     )
),

And Writing a Factory Class UserControllerFactory :

class UserControllerFactory implements FactoryInterface
{
    public function createService(ServiceLocatorInterface $serviceLocator){
        $realServiceLocator = $serviceLocator->getServiceLocator();
        $userService= $realServiceLocator->get('Users\Service\UserServiceInterface');

        return new UsersController($userService);
    }
}

The UserService has a dependency :

'service_manager' => array(
    'factories' => array(
        'Users\Service\UserServiceInterface' => 'Users\Factory\UserServiceFactory',
        'Users\Mapper\PostMapperInterface'   => 'Users\Factory\ZendDbSqlMapperFactory',
     )
),

I get also

Previous exceptions:
Zend\ServiceManager\Exception\ServiceNotCreatedException
File:
D:\wamp\www\AppZend2\vendor\zendframework\zend-servicemanager\src\ServiceManager.php:1101
Message:
While attempting to create usersserviceuserserviceinterface(alias: Users\Service\UserServiceInterface) an invalid factory was registered for this instance type.

this is my UserServiceFactory :

use Users\Service\UserService;
use Zend\ServiceManager\FactoryInterface;
use Zend\ServiceManager\ServiceLocatorInterface;

class UserServiceFactory implements FactoryInterface
{
    public function createService(ServiceLocatorInterface $serviceLocator)
    {
        return new UserService(
            $serviceLocator->get('Users\Mapper\PostMapperInterface')
        );
    }
}