当我把它添加到控制器时，Laravel dd不工作

Question

我的控制器工作正常，但当我使用dd();显示我得到的内容时503 services not available error。

我的相关部门控制器

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Http\Requests;
use App\Order;
use App\AddMonumentSize;
use App\AddHeadstoneDesign;
use App\ImageColor;
use App\DesignCategory;
use App\Shipping;
use App\Billling;
class DesignController extends Controller
{
    public function index()
    {
        $headstone = AddHeadstoneDesign::get(); 
        $sizestone = AddMonumentSize::get();
        $colorstone = ImageColor::get();
        $designCategory = DesignCategory::get();
        return view('design.select_size' , compact('headstone' , 'sizestone' , 'colorstone' , 'designCategory'));
    }

我的路线

Route::get('designer', 'DesignController@index');

任何帮助都将不胜感激。