<?php
$dbname = "database_name";
$dbuser = "database_user";
$dbpass = "database_password";
$dbhost01 = "user.regioninfo.rds.amazonaws.com";
$dbport = 3306;

$dbh = new PDO("mysql:host=$dbhost01;dbname=$dbname", $dbuser, $dbpass);


?>

SQLSTATE[HY000] [2003] Can't connect to MySQL server on 'user.regioninfo.rds.amazonaws.com' (110 "Connection timed out")