MERN社交应用部署Heroku遇H10错误，求排查解决

我跟着YouTube教程开发了一款MERN全栈社交应用，但将Node.js服务器部署到Heroku时遇到了错误：heroku[router]: at=error code=H10。我尝试了所有与该错误相关的解决方案，但都没能解决问题。我已经在Heroku的配置变量中设置了MONGO_URI关联我的MongoDB，并且把启动脚本从nodemon index.js改成了node index.js。

以下是相关代码文件：

package.json #

{
  "name": "server",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "type": "module",
  "scripts": {
    "start": "node index.js"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "bcrypt": "^5.0.1",
    "body-parser": "^1.20.0",
    "cors": "^2.8.5",
    "dotenv": "^16.0.1",
    "express": "^4.18.1",
    "jsonwebtoken": "^8.5.1",
    "mongoose": "^6.5.1",
    "multer": "^1.4.5-lts.1",
    "nodemon": "^2.0.19"
  }
}

index.js #

import express from "express";
import bodyParser from "body-parser";
import mongoose from "mongoose";
import dotenv from "dotenv";
import cors from "cors";
import AuthRoute from "./Routes/AuthRoute.js";
import UserRoute from "./Routes/UserRoute.js";
import PostRoute from "./Routes/PostRoute.js";
import UploadRoute from "./Routes/UploadRoute.js";


// Routes
const app = express();

//Public images
app.use(express.static('public'))
app.use('/images', express.static('images'))

// Middleware
app.use(bodyParser.json({ limit: "30mb", extended: true }));
app.use(bodyParser.urlencoded({ limit: "30mb", extended: true }));
app.use(cors());

dotenv.config();

mongoose
  .connect(process.env.MONGO_URI, {
    useNewUrlParser: true,
    useUnifiedTopology: true,
  })
  .then(() =>
    app.listen(process.env.PORT, () =>
      console.log("Connected")
    )
  )
  .catch((error) => console.log(error));

// Usage of routes

app.use("/auth", AuthRoute);
app.use("/user", UserRoute);
app.use("/posts", PostRoute);
app.use('/upload', UploadRoute);

请问我哪里操作出现了问题？

内容的提问来源于stack exchange，提问作者VicDev