middleware auth in laravel didn't work

My login middle ware didn't work , even it's working fine at local server

and here's my function middle ware

 public function handle($request, Closure $next, $guard = null)
{
    if (Auth::guard($guard)->guest()) {
        if ($request->ajax() || $request->wantsJson()) {
            return response('Unauthorized.', 401);
        } else {
            return redirect()->guest('login');
        }
    }

    return $next($request);
}

It's the default middle ware for laravel make:auth . I think the problem is with my route which here it's :

    Route::get('/', function () {
    return view('welcome');
});
Route::auth();

and here it's my Auth controller :

    class AuthController extends Controller
{
    /*
    |--------------------------------------------------------------------------
    | Registration & Login Controller
    |--------------------------------------------------------------------------
    |
    | This controller handles the registration of new users, as well as the
    | authentication of existing users. By default, this controller uses
    | a simple trait to add these behaviors. Why don't you explore it?
    |
    */

    use AuthenticatesAndRegistersUsers, ThrottlesLogins;

    /**
     * Where to redirect users after login / registration.
     *
     * @var string
     */
    protected $redirectTo = '/';

    /**
     * Create a new authentication controller instance.
     *
     * @return void
     */
    public function __construct()
    {
        $this->middleware($this->guestMiddleware(), ['except' => 'logout']);
    }

    /**
     * Get a validator for an incoming registration request.
     *
     * @param  array  $data
     * @return \Illuminate\Contracts\Validation\Validator
     */
    protected function validator(array $data)
    {
        return Validator::make($data, [
            'name' => 'required|max:255',
            'email' => 'required|email|max:255|unique:users',
            'password' => 'required|min:6|confirmed',
        ]);
    }

    /**
     * Create a new user instance after a valid registration.
     *
     * @param  array  $data
     * @return User
     */
    protected function create(array $data)
    {
        return User::create([
            'name' => $data['name'],
            'email' => $data['email'],
            'password' => bcrypt($data['password']),
        ]);
    }
}

via Dina Shaldoum