NODE JS Express Session lost redirect Payment Gateway

I have an express session, but when I redirect to payment gateway, the gateway return to my page but the session is lost

var session = require('express-session');

app.use(session(
    {
        name: "sessionData",
        secret: "mysecret"
        store: new redisStore({ host: 'localhost', port: 6379, client: client,ttl :  260})
    }
));