Connection Timeout on ubuntu 22.04 (works fine on windows)

Hello,

I'm encountering a connection timeout issue on Ubuntu,
the exact same code works flawlessly on Windows

I'm new to ExpressJS and am trying to create an API using mysql2

I have checked all firewalls, ports, etc., but I'm still facing this problem. i mean It's working on Windows for some reason but not on Ubuntu.

Node.js Version: v20.15.0 on both systems
mysql2: v3.10.2
Database: MariaDB (connecting to the same database on both Windows and Ubuntu)

Error:

Listening on port: 4300
Error connecting to the database: Error: connect ETIMEDOUT
    at PoolConnection._handleTimeoutError (/root/api/node_modules/mysql2/lib/connection.js:205:17)
    at listOnTimeout (node:internal/timers:573:17)
    at process.processTimers (node:internal/timers:514:7) {
  errorno: 'ETIMEDOUT',
  code: 'ETIMEDOUT',
  syscall: 'connect',
  fatal: true
}

Connection code

(async () => {
  try {
    const connection = await pool.getConnection();
    console.log("Connected to the database");
    connection.release();

  } catch (err) {
    console.error("Error connecting to the database:", err);
    process.exit(1);
  }
})();

database file

import dotenv from 'dotenv';
import mysql from 'mysql2/promise';

dotenv.config();

const pool = mysql.createPool({
    host: process.env.HOST,
    user: process.env.USER,
    password: process.env.PASSWORD,
    database: process.env.DATABASE
});

export default pool;

The code is straightforward, I don't understand why it will have problems on Ubuntu.

Start by comparing the Ubuntu and Windows connection environments using the shown database file and pool.getConnection() entry point, including the HOST, USER, PASSWORD, and DATABASE values. Reproduce the ETIMEDOUT error and identify a verified Ubuntu-specific cause; the issue currently names no project test or source file beyond the example configuration.