Use $nodes
instead of $url_list
while initializing the curl. Or use global for $url_list
inside the function.
$curl_array[$i] = curl_init($nodes[$i]);
Your urls are having https, so add this curl option to handle this.
curl_setopt($curl_array[$i], CURLOPT_SSL_VERIFYPEER, false);
Now it should work like a charm for you!