PHP POST not working, what module to enable

I want to make a PHP POST request from my new VPS server to another IP address. I checked the firewall and everything seemed fine but the request never went to the other IP, so I then tried making the same request with node.js and it went through. The question is, what PHP module/extension do I need to enable to allow php requests with or without curl.

A simple CURL request:

$ch = curl_init();
$url='http://example.com/';

curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($data));

curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$server_output = curl_exec ($ch);
curl_close ($ch);
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