Issues creating Admin module controller on Prestashop - module

Question

The controller for URI "/modules/mm_custom/deleter" is not callable. Class "Mm_Custom\Controller\ConfigureController" does not exist.
[InvalidArgumentException 0]
That's what I get after 3 days trying to set an AdminController on my Prestashop module.
Here is the controller "configureController.php":
<?php
// modules/mm_custom/src/controller/configureController.php
namespace Mm_Custom\Controller;
use Symfony\Component\HttpFoundation\Response;
use PrestaShopBundle\Controller\Admin\FrameworkBundleAdminController;
class ConfigureController extends FrameworkBundleAdminController
{
public function deleteAction()
{
return new Response('Hello');
}
}
Here is the routes.yml :
# modules/mm_custom/config/routes.yml
delete:
path: mm_custom/deleter
methods: [GET]
defaults:
_controller: 'Mm_Custom\Controller\ConfigureController::deleteAction'
Here is the composer.json at the module folder root:
{
"name": "sixten/mm_custom",
"description": "A tool developped to allow your customers to easily and efficiently custom your product.",
"autoload": {
"psr-4": {
"Mm_Custom\\Controller\\": "src/Controller/"
}
},
"config": {
"prepend-autoloader": false
},
"type": "prestashop-module"
}
If the problem is not from a mistake in the code himself, it might comes from the fact that I couldn't run the composer dumpautoload console command in the module's folder directly because the website is online on a ftp server.
I put the composer.json somewhere else on my computer, ran the command and copy/paste the composer.json and the vendor file I get in the ftp's module folder. Maybe it's not the good way to do it ?
Thanks for reading me !