Login fcebook Laravel 5.6 Error NotFoundHttpException

<?php

namespace App\Http\Controllers\Auth;

use App\Http\Controllers\Controller;
use Illuminate\Foundation\Auth\AuthenticatesUsers;
use Illuminate\Support\Facades\Redirect;
use Illuminate\Support\Facades\Input;
use Socialite;
use App\User;
use Auth;
use Hash;

class LoginController extends Controller
{
    /*
    |--------------------------------------------------------------------------
    | Login Controller
    |--------------------------------------------------------------------------
    |
    | This controller handles authenticating users for the application and
    | redirecting them to your home screen. The controller uses a trait
    | to conveniently provide its functionality to your applications.
    |
    */

    use AuthenticatesUsers;

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

    /**
     * Create a new controller instance.
     *
     * @return void
     */
    public function index()
	{
		return view('home');
	}
    
    public function __construct()
    {
        $this->middleware('guest')->except('logout');
    }
    
     /**
     * Redirect the user to the facebook authentication page.
     *
     * @return Response
     */
    public function facebookAuthRedirect()
    {
        return Socialite::with('facebook')->redirect();
    }

    /**
     * Obtain the user information from GitHub.
     *
     * @return Response
     */
    public function facebookSuccess()
    {       
        $provider = Socialite::with('facebook');
        if (Input::has('code')){
            $user = $provider->stateless()->user();
            //dd($user); // print value debug.
            $email = $user->email;
	    	$name  = $user->name;
	    	$password = substr($user->token,0,10);
	    	$facebook_id = $user->id;
            
            //เช็คว่า email เป็น null หรือไม่
              if($email == null){ // case permission is not email public.
                $user = $this->checkExistUserByFacebookId($facebook_id);
                  
            if($user == null){
                $email = $facebook_id;
                   }
                }
                else
                {
                       $user = $this->checkExistUserByEmail($email);
                        if($user != null){
                            if($user->facebook_id == ""){ // update account when not have facebook id.
                                $user->facebook_id = $facebook_id;
                                $user->save();
                        }
                    }
                }
            
                    if($user!=null){ // Auth exist account.
                        Auth::login($user);
                        return redirect('index/');
                    }
                    else{ // new Account.
                        $user = $this->registerUser($email,$name,$password,$facebook_id);
                        Auth::login($user);
                        return redirect('index/');
                    }
                }
                return redirect('/');
            }
    
    //เช็คว่าเป็นสมาชิกเดิมหรือปล่าวเช็คว่าเป็นสมาชิกเดิมหรือปล่าว
    private function checkExistUserByEmail($email)
    {
        $user = \App\User::where('email','=',$email)->first();
        return $user;
    }

    private function checkExistUserByFacebookId($facebook_id)
    {
        $user = \App\User::where('facebook_id','=',$facebook_id)->first();
        return $user;
    }

    //Member Register
    private function registerUser($email,$name,$password,$facebook_id)
    {
            $user = new \App\User;
            $user->email = $email;
            $user->name = $name;
            $user->password = Hash::make($password); // Hash::make
            $user->balance = 0;
            $user->level = "member";
            $user->facebook_id = $facebook_id;
            $user->save();

            return $user;
    }
}

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

Auth::routes();

Route::get('/home', 'HomeController@index')->name('home');

// for redirect to facebook auth.
Route::get('login/facebook', 'Auth\LoginController@facebookAuthRedirect');
// facebook call back after login success.
Route::get('login/facebook/callback', 'Auth\LoginController@facebookSuccess');