Level 1 authentication - node.js

Question

Good day, Please help me find the error in my code for level one authentication I could create a database, register users and store in their inputs using body parser, but I couldn't login already registered users. the login page keeps loading till it tells me a connection error, please help me out
const express = require("express");
const bodyParser = require("body-parser");
const ejs = require("ejs");
const mongoose = require("mongoose");
const app = express();
app.use(express.static("public"));
app.set('view-engine', 'ejs');
app.use(bodyParser.urlencoded({
extended: true
}));
mongoose.connect("mongodb://localhost:27017/User", {useNewUrlParser: true});
const userSchema = ({
email: String,
password: String
});
const User = new mongoose.model("User", userSchema);
const users = []
app.get("/", function(req, res){
res.render("first.ejs");
});
app.get("/login", function(req, res){
res.render("login.ejs");
});
app.get("/register", function(req, res){
res.render("register.ejs");
});
app.post("/register", function(req, res){
const newUser = new User({
email: req.body.username,
password: req.body.password
});
newUser.save(function(err){
if (err) {
console.log(err);
} else {
res.render("home.ejs");
}
});
});
app.post("/login", function(req, res){
const username = req.body.username;
const password = req.body.password;
User.findOne({email: username}, function(err, foundUser){
if (err) {
console.log(err);
} else {
if (foundUser) {
if (foundUser.password === password) {
res.send("hi");
}
}
}
});
});
app.listen(3000, function() {
console.log("Server started on port 3000.");
});