Express session, passport and connect-pg-simple issue in production

Question

This is my first time posting a question up here. I hope you guys can help me out with this. I am fairly new to node.js, express, so sorry in advance for my inexperience.

I am currently having a problem with my authentication session in my node.js, express app. I use Passport.js to handle my authentication, I store the login session with connect-pg-simple (a PostgreSQL session store). After clicking the login button, the session was stored inside my PostgreSQL database, but somehow express couldn't find it. In fact, it stores the session twice in the database, but only one of them got the passport cookie in it.

This issue was not present when the server was still on localhost. It appears when I host my server on Heroku.

Also, whenever I push to heroku repo, it shows this warning:

"connect.session() MemoryStore is not designed for a production environment, as it will leak memory, and will not scale past a single process."

My guess is I didn't connect express session to the PostgreSQL express store properly. Below is my code:

This is how I set up the PostgreSQL database:

const Pool = require("pg").Pool;

const pool = new Pool({
    user: process.env.PGUSER,
    password: process.env.PGPASSWORD,
    host: process.env.PGHOST,
    port: process.env.PGPORT,
    database: process.env.PGDATABASE
});


module.exports = pool

This is how I set up the session:

const poolSession = new (require('connect-pg-simple')(session))({
    pool : pool    
  })

app.set('trust proxy', 1);
app.use(session({
    store: poolSession, 
    secret: process.env.SESSION_SECRET,
    saveUninitialized: true,
    resave: false,
    cookie: { 
        secure: true,
        maxAge: 30 * 24 * 60 * 60 * 1000
    } // 30 days
}));

app.use(passport.initialize());
app.use(passport.session());

This is the image of 2 sessions were store in the database when clicking the login button https://i.stack.imgur.com/lzAby.png

This is my login route (when click the login button):

router
    .route("/signin")
    .post((req, res, next) => {
        console.log("Signing in...")
        passport.authenticate('local', function(err, user, info) {
            //code....

            req.logIn(user, function(err) {[enter image description here][1]
                console.log(user);
                if (err) { 
                    console.log(err);
                    res.send(apiResponse(500, err.message, false, null))
                    return next(err); 
                }
                console.log(req.sessionID); //The id of the 1st session store in db
                console.log(req.isAuthenticated()) //True
                res.redirect('/auth');
            });
        })(req, res, next);
    })

This is the route that is redirected to when login successfully:

router.get("/", (req, res) => {
        console.log("/ ", req.isAuthenticated()); //False
        console.log("/ ", req.sessionID); //The Id of the 2nd session store in db 
        if(req.isAuthenticated()){
           //Notify user login success
        } 
    });

I have been stuck here for a few days now. Please tell me if you need more code!