NodeJs port only works via local network

I set up a simple NodeJs server:

var express = require('express');
var app = express();
app.get('/', function(req, res){
    res.send('hello world'); // try res.json() if getList() returns an object or array
});
app.listen(3000);

Now when i visit http://server.domain.com:3000/ on the local network, i receive the correct response, but on 3G mobile device i recieve a no response timeout.

Server is equipped csf v6.28 Firewall

I will need the script to be accessible by all users..