Why are sessions not saved?

Question

JavaScript

Hello.
I decided to try to add the possibility of authorization in the application through sessions,
but they are not saved.
I'm running it on my local machine ( localhost:3000/).
Code mixed from the official example and other guides:

app.use(session({
  secret: 'some_pass',
  resave: true,
  saveUninitialized: true,
  cookie: { httpOnly: false,
            maxAge  : 24*60*60*1000,
            secure: false,
            resave: false,
            saveUninitialized: true,
            unset: 'destroy',
            domain: 'http://localhost:3000' }
}));
app.get('/', (req, res) => {
  res.json(req.session);
  req.session.test = "1";
})

It is clearly visible. When the page is loaded, the current session is displayed, and a new variable is added to it. However, after reloading the page, it is not visible.