Unable to connect Backend on other network

I am making a group project in which one member doing Frontend and I am doing Backend . I what that using my IP he connect with Backend
When my laptop and his laptop both are in same network and I add his IP in cors then it works but when he is on different , he is unable to communicate with my Backend

My backend is in Node.js & Express.js

I am in ubuntu so I allow my port from firewall using

sudo ufw allow 8080

also use differant cors options like,

app.use(cors({
  origin: '*',
  methods: ['GET', 'POST', 'PUT', 'DELETE', 'OPTIONS'],
  allowedHeaders: ['Content-Type', 'Authorization']
}))

and

app.use(cors())

and I listen on 0.0.0.0

const server = app.listen(PORT, '0.0.0.0', () => {
   console.log(`Server started on port ${PORT}`);
});

but still my friend is unable to access my Backend . I want to make it universal , means who enter my ip and port he can access like : 192.168.xx.xxx:8080/