After mongodb starts the service, why does post exit directly after a single request?

I don"t understand why there is something wrong with mongodb"s connection after writing a login interface. As long as a login request is sent, after the request ends, its service will exit directly.

when starting the service, connect to the database:

const mongoose = require("mongoose");
const db = require("../db/config/key").mongoURI;
//connect db
mongoose.connect(db,{ useNewUrlParser: true }).then( () => console.log("DB Successful")).catch((err) => console.log(err));

here is my login interface:

/** 
 * authenticate()3nameoptions
*/
router.post("/login",urlencodedParser,(req,res,next) => {
    const loginUser = {
        email:req.body.email,
        password:req.body.password
    };

    console.log(loginUser);
    passport.authenticate("local", {
      successRedirect:"/",
      failureRedirect: "/admin/login",
      failureFlash: true
    })(req, res, next);

    // UserSchema.findOne({
    //     email:loginUser.email
    //   }).then(users => {
    //     console.log("user" + users)
    //     if(!users){
    //       return done(null, false, {message: "No User Found"});
    //     } 
    //     //
    //     bcrypt.compare(loginUser.password, users.password, (err, isMatch) => {
    //       if(err) throw err;
    //       if(isMatch){
    //         res.redirect("/")
    //       } else {
    //         res.redirect("/admin/login")
    //       }
    //     })
    //   })
  });

passport.js

const UserSchema = require("../models/UserSchema");


module.exports = function(passport){
  passport.use(new LocalStrategy({usernameField: "email"}, (email, password, done) => {
    console.log(":" + email+"/"+ password)
    // Match user
    UserSchema.findOne({
      email:email
    }).then(users => {
      console.log("user" + users)
      if(!users){
        return done(null, false, {message: "No User Found"});
      } 

      // Match password
      bcrypt.compare(password, users.password, (err, isMatch) => {
        console.log("password   " + password);
        console.log("user.password" + users.password);
        if(err) throw err;
        if(isMatch){
          console.log("isMatch   " + isMatch)
          // token
          // const rule = {
          //     id: users._id,
          //     email:users.email,
          //     admin:"true"
          // };

          // jwt.sign(rule,secretKey,{expiresIn:3600},(err,token) => {
          //   if(err) throw err;
          //   res.json({
          //       sucess:true,
          //       token:"Bearer " + token
          //   });
          // });
          return done(null, users);
        } else {
          return done(null, false, {message: "Password Incorrect"});
        }
      })
    })
  }));

as long as you make a request, you will exit directly, and then there will be such a prompt in the window, which will be broken again.

{ MongoNetworkError: failed to connect to server [localhost:27017] on first connect [MongoNetworkError: connect ECONNREFUSED 127.0.0.1:27017]
    at Pool.<anonymous> (E:\API\anviz\anviz\web\node_modules\mongodb-core\lib\topologies\server.js:564:11)
    at Pool.emit (events.js:182:13)
    at Connection.<anonymous> (E:\API\anviz\anviz\web\node_modules\mongodb-core\lib\connection\pool.js:317:12)
    at Object.onceWrapper (events.js:273:13)
    at Connection.emit (events.js:182:13)
    at Socket.<anonymous> (E:\API\anviz\anviz\web\node_modules\mongodb-core\lib\connection\connection.js:246:50)
    at Object.onceWrapper (events.js:273:13)
    at Socket.emit (events.js:182:13)
    at emitErrorNT (internal/streams/destroy.js:82:8)
    at emitErrorAndCloseNT (internal/streams/destroy.js:50:3)
    at process._tickCallback (internal/process/next_tick.js:63:19)
  name: "MongoNetworkError",
  errorLabels: [ "TransientTransactionError" ],
  [Symbol(mongoErrorContextSymbol)]: {} }

I have mongodb configured locally and a service to add mongodb in windows.
when the computer is started, the mongodb service is also started. The configuration in windows startup service is: E:APIDBbinmongod.exe-- bind_ip 192.168.70.181-- logpath E:APIDBlogmongodb.log-- logappend-- dbpath E:APIDBdatadb-- port 27017-- service

but every time the service starts, it must be manually typed: mongod.exe-- dbpath E:APIDBdatadb will start successfully, and then the manually started service can only be used once, and the request will be cut off directly?

May I ask what the reason is?
very anxious, thank you very much!

Mongodb

May.11,2022