将html表单数据发送到nodejs服务器时出错

<form action="/submit" method="POST">
  <input type="text" name="username" />
  <input type="password" name="password" />
  <button type="submit">Submit</button>
</form>

const express = require('express');
const app = express();

app.use(express.urlencoded({ extended: true }));

app.post('/submit', (req, res) => {
  console.log(req.body);
  res.send('Data received');
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});

const express = require('express');
const app = express();

app.use(express.urlencoded({ extended: true }));

app.post('/submit', (req, res) => {
  console.log(req.body);
  res.send('Data received');
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});

const express = require('express');
const cors = require('cors');
const app = express();

app.use(cors());
app.use(express.urlencoded({ extended: true }));

app.post('/submit', (req, res) => {
  console.log(req.body);
  res.send('Data received');
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});

lsof -i :3000