Connection timed out with IPN call especially for sandbox.paypal.com - paypal

Question

Following is the sample code:
$req = "122";
$header = "POST /cgi-bin/webscr HTTP/1.1\r\n";
$header .= "Host: www.sandbox.paypal.com\r\n";
$header .= "Connection: close\r\n";
$header .= "Content-Type: application/x-www-form-urlencoded\r\n";
$header .= "Content-Length: " . strlen($req) . "\r\n\r\n";
$fp = fsockopen ('ssl://www.sandbox.paypal.com', 443, $errno, $errstr, 30);
if(!$errno)
{
var_dump($fp);
}
else
{
echo "ERROR: $errno, $errstr";
}
When I connect to the sandbox it produces me a connection timed out error:
ERROR: 110, Connection timed out
So I debugged the problem and found out it was something to do with the SSL and verified the existence and accessibility of openssl in the server.
Tested the openssl and connectivity on the server with the following
"openssl s_client -connect www.sandbox.paypal.com:443"
I get
"Socket: Connection Timed out"
I checked out iptables and there is no blocking for port 443
So I tried again to check the case for paypal.com, like the following:
$fp = fsockopen ('ssl://www.paypal.com', 443, $errno, $errstr, 30);
It worked immediately.
So I tried in my other server and I was able to connect to sandbox.paypal.com but not on the server where I need to demo and test payments.
My hosting provider is clueless and I am pulling my hair out here.
I appreciate any help on this.
Yes, ofcourse my first question on Stackoverflow :)