当我尝试打开heroku应用程序时为什么会出现此问题

Question

我在尝试打开我的heroku应用程序时遇到此错误。

https://itacateserver.herokuapp.com/

该应用无法打开。我将其用作服务器，并使用节点js进行编码。

这是我的index.js

const express = require("express");
const bodyParser = require("body-parser");
const logger = require("morgan");
const methodOverride = require("method-override");
const cors = require("cors");
const serverPort = process.env.PORT || 3568;
const app = express();
const route = express.Router();
//Settings
app.set("port", serverPort);
// Middlewares
app.use(express.json());
app.use(logger("dev"));
app.use(bodyParser.json());
app.use(methodOverride());
app.use(cors());

// Cors
app.use((req, res, next) => {
  res.header("Access-Control-Allow-Origin", "*");
  res.header(
    "Access-Control-Allow-Headers",
    "Origin, X-Requested-With, Content-Type, Accept"
  );
  next();
});

//rutas
// mensaje de bienvenida
app.get("/", (req, res) => {
  res.send("Welcome to the itacate's app & web api.");
});

可能是什么问题？

这是package.json

{
  "name": "itacateserver",
  "version": "0.0.1",
  "description": "Servidor de la app de itacate",
  "main": "index.js",
  "scripts": {
    "start": "node .",
    "dev": "nodemon ."
  },
  "author": "",
  "license": "",
  "dependencies": {
    "body-parser": "^1.19.0",
    "cookie-parser": "^1.4.5",
    "cors": "^2.8.5",
    "express": "^4.17.1",
    "method-override": "^3.0.0",
    "multer": "^1.4.2",
    "passport-local": "^1.0.0",
    "bcryptjs": "^2.4.3",
    "express-mysql-session": "^2.1.4",
    "morgan": "^1.10.0",
    "mysql": "^2.18.1",
    "passport": "^0.4.1",
    "timeago.js": "^4.0.2"
  },
  "devDependencies": {
    "nodemon": "^2.0.6"
  }
}

我认为此错误可能与“开发”和“启动”有关