这是我的连接文件

const connectDB = async () =>{
        const conn = await new mongoose("mongodb+srv://nikunj:gadia7420@cluster0.94xph.mongodb.net/myFirstDatabase?retryWrites=true&w=majority",
        {
            usenewurlparser:true,
            usecreateindex:true,
            usefindmodify:true,
            useunifiedtropology:true,
            urlencoded:true
        })
}
module.exports = connectDB;

这是我的模型文件

const userSchema = new mongoose.Schema({
    username:{
        type:String,
        required:true
    },
    avatar:{
        type:String,
    },
    email:{
        type:String,
        required:true
    },
    password:{
      type  : String,
     required:true
    }
});
module.exports = mongoose.model('user',userSchema);

此文件将插入信息或从数据库中获取信息以进行注册

const express = require('express');
const router = express.Router();
const User = require('../models/user');
const bcrypt= require('bcrypt');

router.post('/register',async(req,res,next)=>{
    const  {username,email,password}=req.body;
    try{
        let user_exist = await User.findOne({email:email});
        if(user_exist){
            success="false";
            msg="user already exist";
        } else {
            //importing data to models
            let user = new User();
            user.username = username;
            user.email = email ;
            const salt = await bcrypt.genSalt(10);
            user.password =  await bcrypt.hash(password,salt),
            user.avatar =  "https://gravatar.com/avatar/?s=200&d=retro"
            await user.save();
            res.json({
                sucess:true,
                user:user,
                msg:"user registered"
            })
        }
    }
    catch(err){
        console.log(err);
    }
});

module.exports = router;

这是我的主文件（server.js）

const express = require('express');
const morgan = require('morgan');
const colors = require('colors');
const dotenv = require('dotenv');
const mongoose = require('mongoose');
const connectDB = require('./config/db');
//creating main platform
connectDB;
console.log(mongoose.connection.readyState);
const app = express();
app.use(morgan('dev'));
dotenv.config({
    path:'./config/config.env'
})
app.use(express.json({}))
app.use(express.json({
    extended:true
}))

//creating server
app.use('/api/todo/auth',require('./routes/user'));
const Port = process.env.port;
app.listen(Port,
    console.log(`listening on port :${Port}` .red.underline.bold));
//creating req,res platform

但运行此程序后，在发出post请求时显示错误

MongooseError: Operation `users.findOne()` buffering timed out after 10000ms
    at Timeout.<anonymous> (D:\nikunj\Programming\todoapp\node_modules\mongoose\lib\drivers\node-mongodb-native\collection.js:185:20)
    at listOnTimeout (node:internal/timers:556:17)
    at processTimers (node:internal/timers:499:7)

请找到一个解决方案。谢谢。对不起，如果这是一个愚蠢或错误的问题，因为我是新来的这个节点