Can't install Silex webprofiler

Question

I work on a Silex project, but I can not install the webprofiler. I followed the official installation of the web profiler for Silex (https://github.com/silexphp/Silex-WebProfiler) but this returns a 500 error.

My code :

//I do not use "MonologServiceProvider".
use Silex\Provider;
//Twig provider is already register.
$app->register(new Provider\HttpFragmentServiceProvider());
$app->register(new Provider\ServiceControllerServiceProvider());
// I have no error here.


//But if i add this, this returns a 500 error.
$app->register(new Provider\WebProfilerServiceProvider(), array(
    'profiler.cache_dir' => __DIR__.'/../cache/profiler',
    'profiler.mount_prefix' => '/_profiler', // this is the default
));

$app->run();

This is my arborescence:

The bundle webprofiler is in the vendor / silex / web-profiler directory which has the namespace 'Silex \ Provider'. But there is also a "Silex \ Provider" namespace in the Silex / silex folder. So I was wondering if he was not going to look into the wrong folder.

This just returns a 500 error ..

Any help will be appreciated. Thanks !