cURL和file_get_contents都不能加载某些网页

I am running an IIS 8 / PHP web server and am attempting to write a so-called 'proxy script' as a means of fetching HTTP content and loading it onto an HTTPS page.

Although the script does run successfully (outputting whatever the HTTP page sends) in some cases - for example, Google.com, Amazon.com, etc. - it does not work in fetching my own website and a few others.

Here is the code of proxy.php:

<?php
$url = $_GET['url'];

echo "FETCHING URL<br/>";      // displays this no matter what URL I enter 
$ctx_array = array('http' =>
    array(
        'method' => 'GET',
        'timeout' => 10,
    )
);
$ctx = stream_context_create($ctx_array);
$output = file_get_contents($url, false, $output);  // times out for certain requests
echo $output;

When I set $_GET['url'] to http://www.ucomc.net, the script fails. With most other URLs, it works fine.

I have checked other answers on here and other places but none of them describe my issue, nor do the solutions offered solve it.

I've seen some suggestions to similar problems that involve changing the user agent, but when I do this it not only does not solve the existing problem but prevents other sites from loading as well. I do not want to rely on third-party proxies (don't trust the free ones/want to deal with their query limit and don't want to pay for the expensive ones)

Turns out that it was just a problem with the firewall. Testing it on a PHP sandbox worked fine, so I just had to modify the outgoing connections settings in the server firewall to allow the request through.