Node authentication, when I submit credentials nothing happens - node.js

Question

I've built a practice authentication app and it originally worked right when I built it. Now when I try to login or register nothing happens. I can see in my database that it registers a new user but it doesn't move me onto the secret page. When I login with correct credentials and submit it just sits on the login page (but removes the credentials from the form). I've tried to use failureFlash in the login post route but it just errors that it's not a function. I'm not sure what else to do to troubleshoot.
user model:
const mongoose = require("mongoose"),
passportLocalMongoose = require("passport-local-mongoose");
var UserSchema = new mongoose.Schema({
username: String,
password: String
});
UserSchema.plugin(passportLocalMongoose);
module.exports = mongoose.model("User", UserSchema);
app.js:
const express = require("express"),
app = express(),
mongoose = require("mongoose"),
bodyParser = require("body-parser"),
passport = require("passport"),
LocalStrategy = require("passport-local"),
passportLocalMongoose = require("passport-local-mongoose"),
expressSession = require("express-session"),
User = require("./models/user"),
mdbUrl = "This is the url and credentials to my database";
app.set("view engine", "ejs");
app.use(bodyParser.urlencoded({extended:true}));
app.use(passport.initialize());
app.use(passport.session());
passport.use(new LocalStrategy(User.authenticate()));
passport.serializeUser(User.serializeUser());
passport.deserializeUser(User.deserializeUser());
app.use(expressSession({
secret: "some string",
resave: false,
saveUninitialized: false
}));
mongoose.connect(mdbUrl,{useNewUrlParser: true, useCreateIndex: true, useUnifiedTopology: true})
.then(()=> {
console.log("mongooooooose");
})
.catch(err=> {
console.log(err);
})
app.get("/", (req, res)=>{
res.render("home");
});
app.get("/secret", isLoggedIn, (req,res)=>{
res.render("secret");
});
app.get("/register", (req,res)=>{
res.render("register");
});
app.post("/register", (req, res)=>{
req.body.username;
req.body.password;
User.register(new User({username: req.body.username}), req.body.password, (err, user)=>{
if(err){
console.log(err);
res.redirect("register");
}
passport.authenticate("local")(req, res, ()=>{
res.redirect("/secret");
});
});
});
app.get("/login", (req, res)=>{
res.render("login");
});
app.post("/login", passport.authenticate("local",{
successRedirect: "/secret",
failureRedirect: "/login",
}), (req,res)=>{});
app.get("/logout", (req, res)=>{
req.logout();
res.redirect("/");
});
function isLoggedIn(req, res, next){
if(req.isAuthenticated()){
return next();
}
res.redirect("/login");
}
app.listen(3000, ()=>{
console.log("auth started");
});
login.ejs:
<h1>Login</h1>
<form action="/login" method="POST">
<input type="text" placeholder="username" name="username">
<input type="password" placeholder="password" name="password">
<button>Submit</button>
</form>
secret.ejs:
<h1>
Secret Page
</h1>
<p>
this is a test page
</p>
<li>Sign Up!</li>
<li>Sign in</li>
<li>log out</li>
register.ejs:
<h1>register</h1>
<form action="/register" method="POST">
<input type="text" placeholder="username" name="username">
<input type="password" placeholder="password" name="password">
<button>Submit</button>
</form>
<li>Sign Up!</li>
<li>Sign in</li><li>log out</li>