我创建了一个网站，前端使用React，后端使用nodejs express。然而，当我尝试从前端调用其中一个后端函数时，请求需要2分钟，然后在控制台中返回此错误：

POST http://evogenesis.co.uk:3000/nodeapp/api/register net::ERR_EMPTY_RESPONSE
(anonymous) 
script.js:17

react_devtools_backend.js:2655 Error: TypeError: Failed to fetch
    at HTMLButtonElement.<anonymous> (<anonymous>:24:3)

这是我的script.js文件中的前端函数：

// Register new user and save todo list to database
registerButton.addEventListener('click', function() {
  const email = emailInputRegister.value;
  currentuseremail = email;
  const todoList = [];
  const data = { email: email, todoList: todoList };
  fetch('http://evogenesis.co.uk:3000/nodeapp/api/register', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify(data)
  })
  .then(response => {
      if (!response.ok) {
        throw new Error('Network response was not ok');
      }
      return response.json();
  })
  .then(data => {
      console.log('Success:', data);
  })
  .catch(error => {
      console.error('Error:', error);
      console.log(data);
  });
});

它调用另一个名为app.py的文件中的后端函数。它位于一个名为nodeapp的文件夹中，该文件夹与script.py（public_html目录）在同一个目录中。下面是整个app.js文件：

const express = require('express');
const mysql = require('mysql');
const cors = require('cors');
const bodyParser = require('body-parser');
const path = require('path');

const app = express();
const port = 3000;

// Create connection to MySQL database
const connection = mysql.createConnection({
  host: '127.0.0.1',
  user: 'evogenes_shbc',
  password: 'mitsMysq27',
  database: 'evogenes_Users'
});

// Use bodyParser middleware to parse JSON data
app.use(bodyParser.json());

app.use(cors)
// Serve static files from public directory
app.use(express.static(path.join(__dirname, '/')));

// Register new user and save todo list to database
app.post('/api/register', function() {
  const email = req.body.email;
  console.log(email);
  const todoList = JSON.stringify(req.body.todoList);
  console.log(todoList);
  const query = `INSERT INTO users (username, todo_list) VALUES (?, ?)`;
  console.log(query);
  connection.query(query, [email, todoList], function(error) {
    if (error) {
      console.error('Error registering user:', error);
      res.status(500).json({ error: error.message });
    } else {
      res.sendStatus(200);
    }
  });
  console.log("query done");
});

app.post('/api/save', function(req, res) {
    console.log("saving")

    const email = req.body.email;
    const todoList = JSON.stringify(req.body.todoList);
    const query = `UPDATE users SET todo_list = ? WHERE username = ?`;

    console.log(email);

    connection.query(query, [todoList, email], function(error) {
        if (error) {
            console.error('Error registering user:', error);
            res.sendStatus(500);
          } else {
            res.sendStatus(200);
        } 
    });
});

// Start server
app.listen(port, function() {
  console.log(`Server listening on port sdfsd`);
});

整个事情是运行在一个Node.js应用程序，我通过我的网络托管提供商（ifastnet）设置。我已经通过提供的GUI启动了应用程序，但我想我也可以尝试通过他们提供的终端运行它，但当我在nodeapp目录中运行node app.js时，我得到了这个错误：

events.js:160
      throw er; // Unhandled 'error' event
      ^

Error: listen EADDRINUSE :::3000
    at Object.exports._errnoException (util.js:1020:11)
    at exports._exceptionWithHostPort (util.js:1043:20)
    at Server._listen2 (net.js:1271:14)
    at listen (net.js:1307:10)
    at Server.listen (net.js:1403:5)
    at EventEmitter.listen (/home/evogenes/nodevenv/public_html/nodeapp/10/lib/node_modules/express/lib/application.js:635:24)
    at Object.<anonymous> (/home/evogenes/public_html/nodeapp/app.js:64:5)
    at Module._compile (module.js:577:32)
    at Object.Module._extensions..js (module.js:586:10)
    at Module.load (module.js:494:32)

当我尝试通过postman向http://evogenesis.co.uk/nodeapp/api/register地址发出请求时，它会抛出以下错误：

{
    "status": "error",
    "message": "Incomplete response received from application"
}

我试过检查错误日志（据我所知，node.js应用的ifastnet错误消息会发送到您指定的日志文件中。然而，日志文件只包含以下内容：

App 11205 output: Server listening on port sdfsd
App 8735 output: Server listening on port sdfsd
App 31095 output: Server listening on port sdfsd
App 10462 output: Server listening on port sdfsd
App 5055 output: Server listening on port sdfsd

同样，没有新记录被添加到mysql数据库的表中（也由ifastnet提供）。为什么会出现这个问题，我如何解决它？我可以提供HTML页面的完整代码，如果需要的话，可以提供JavaScript前端的其余代码。