Why doesn't it redirect when registering in node.js?

Question

Node.js

Good afternoon everyone, please tell me why I am not being redirected to the page specified in the code upon successful registration? I am registering using passport.js + sequelize(postgressql), in the code below (router), when the user enters data, a redirect should work, the passport.js code is written correctly, since the data is added to the table during registration, but at the same time, everyone I am not being redirected to the specified index page, it says that the page is unavailable after some time, why? the page exists, and if you don’t make a registration request, but just start the server and go to /index, then everything is displayed well, but when the registration request comes in and the data is added to the database, then all the pages seem to die off, I can’t go anywhere until I restart the server

const passport = require('passport');
const { Router } = require('express');
const router = new Router();

router.get('/signup', (req, res) => {
    res.render('signup');
});

router.get('/index', (req, res) => {
    res.render('index');
});

router.post('/signup', passport.authenticate('signup', {
       successRedirect: '/index', //из passport.use берется signup
       failureRedirect: '/signup',
       failureFlash: true
     }));
module.exports = router;

Answer 1

Most likely the problem is that you need to import the passport file that you described.
const passport = require('Путь до файла');