Express应用程序在Azure上成功部署,但仍然无法运行

Azure已成功部署此应用程序,但主页响应为500状态

index.js:

const express = require("express");

const app = express();

app.get("/", (req, res) => {
  res.send("Hello!");
});

app.listen(3000, () => console.log("Hwllo!"));

package.json:

  "name": "test",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "start": "node index.js",
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "express": "^4.17.1"
  }
}