Cant access the session from another route

Im using client-sessions and this is my code:

app.post("/login", (req, res)=>{

    if (!req.session.activeUser){
        User.findOne({username:req.body.username}).then(doc=>{
            req.session.activeUser = req.body.username
            res.send(req.session.activeUser + " Logged in successfully")
        }).catch(e=>{
            res.send(e)
        })
    }else {
        res.redirect("/")
    }

})

app.get("/logout", (req, res)=>{
        req.session.reset()
        res.redirect("/")
})

app.get("/online", (req, res)=>{
    res.send(JSON.stringify(req.session))
    console.log(JSON.stringify(req.session))
})

The response of /login works well, but the controller /online returns an empty object.

I've tried express-session and got the same problem

via BaHaa Jr.