https getting redirected and not working

Hi,

Moodle 2.5.1

LAMP environment

I am having trouble setting up https access for my site. The https setup has been set on the apache server. I have 2 sites running on the same server

Site 1: config.php

<?php // Moodle configuration file

unset($CFG);
global $CFG;
$CFG = new stdClass();

$CFG->dbtype = 'mysqli';
$CFG->dblibrary = 'native';
$CFG->dbhost = 'localhost';
$CFG->dbname = 'aaaa';
$CFG->dbuser = 'aaaa';
$CFG->dbpass = 'aaaa';
$CFG->prefix = 'mdl_';
$CFG->dboptions = array (
'dbpersist' => 0,
'dbsocket' => 0,
);

$CFG->wwwroot = 'https://site1.xxxx.com';
$CFG->dirroot = '/var/www/html/moodle.site1';
$CFG->dataroot = '/opt/moodledata';
$CFG->admin = 'admin';

$CFG->directorypermissions = 0777;

$CFG->passwordsaltmain = .......;

require_once(dirname(__FILE__) . '/lib/setup.php');

// There is no php closing tag in this file,
// it is intentional because it prevents trailing whitespace problems!
?>

Site 2: this site runs on Moodle 1.9 and was initially put in place before site 1 was added to the server

<?php // Moodle configuration file

unset($CFG);
global $CFG;
$CFG = new stdClass();

$CFG->dbtype = 'mysqli';
$CFG->dblibrary = 'native';
$CFG->dbhost = 'localhost';
$CFG->dbname = 'aaaa';
$CFG->dbuser = 'aaaa';
$CFG->dbpass = 'aaaa';
$CFG->prefix = 'mdl_';
$CFG->dboptions = array (
'dbpersist' => 0,
'dbsocket' => 0,
);

$CFG->wwwroot = 'https://site2.xxxx.com';
$CFG->dirroot = '/var/www/html/moodle.site2';
$CFG->dataroot = '/opt/moodledata';
$CFG->admin = 'admin';

$CFG->directorypermissions = 0777;

$CFG->passwordsaltmain = .......;

require_once(dirname(__FILE__) . '/lib/setup.php');

// There is no php closing tag in this file,
// it is intentional because it prevents trailing whitespace problems!
?>

The problem occuring is that the site https://site1.xxxx.com gets redirected to https://site2.xxxx.com

If I changes the url from https to http for site 1 then it works. it is only when I change to https  that it gets redirected to the site 2. Our server hosting provide says that they ran a curl command which showed it returned a 200 OK 

Any ideas why this redirect is happening even though there are no redirect rules setup on the webserver?

Thanks in advance

vijay