I think to connect to mongoose we might need to connect this way. mongoose.connect(MONGO_URI).then(() => { console.log("connected to mongodb"); }).catch((e) => { console.log("could not connect to mongodb", e); }); We would als need to install @types/cookie-session And I think the logout function should be implemented this way router.get("/logout", (req: Request, res: Response) => { req.logout(function(err) { if (err) { console.error('error when logging out', err); } res.redirect("/"); }); });