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( "/" ); }); });