laravel showing 1 after i login - laravel

Question

When I log in Laravel, first thing that shows is 1 then it redirects me to my intended page. I have checked everywhere, there is no middleware which makes 1 to show up. I don't get what is the problem.
This is my login code:
namespace App\Http\Controllers\Auth;
use App\Http\Controllers\Controller;
use App\Providers\RouteServiceProvider;
use Illuminate\Foundation\Auth\AuthenticatesUsers;
use Illuminate\Support\Facades\Auth;
use Illuminate\Support\Facades\Request;
use Illuminate\Support\Facades\Session;
class LoginController extends Controller
{
use AuthenticatesUsers;
public function __construct()
{
$this->middleware('guest')->except('logout');
}
protected function authenticated()
{
return redirect('admin/dashboard');
}
public function showLoginForm()
{
return view('admin.login');
}
protected function validateLogin(Request $request)
{
$request->validate([
'email' => 'required',
'password' => 'required'
]);
}
public function logout()
{
session::flush();
auth::logout();
return back();
}
}
These are my routes
use Illuminate\Support\Facades\Route;
/*
|--------------------------------------------------------------------------
| Web Routes
|--------------------------------------------------------------------------
|
| Here is where you can register web routes for your application. These
| routes are loaded by the RouteServiceProvider within a group which
| contains the "web" middleware group. Now create something great!
|
*/
// Route::get('/', function () {
// return view('welcome');
// });
Auth::routes();
// Route::get('/home', 'HomeController#index')->name('home');
Route::post('/login', 'Auth\LoginController#attemptLogin')->name('login');
Route::middleware('auth')->prefix('/admin')->name('admin.')->group(function() {
Route::get('/dashboard', 'DashboardController#index')->name('dashboard');
Route::post('/logout', 'Auth\LoginController#logout')->name('logout');
});
There is not much in my routes as I just started to build my site and I am facing this error.