Curl issue – “couldn’t connect to host”

I have one plugin which you install on wp site and then need to connect it with my production site. For this connection I use CURL request.

I have problem with one wordpress site installed on wpengine. It worked fine for a long time and then suddenly CURL is unable to connect with my production site from this wp site on wpengine.

In curl_error($ch) I am getting “Couldn't connect to host“, and I have this problem only with this one site which is one wpengine.

This is my CURL code for connection

    $vars = json_encode (
            array(
                //some params
            )
    );

    $headers = array(
        'Accept: application/json',
        'Content-Type: application/json',
    );
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, 'https://myproduction.com/');
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $vars);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
    $result = curl_exec($ch);
    return json_decode($result); 

This prolem was happening some time and then suddenly It start to work fine with myproduction site again and all works fine, but now I cannot to connect it with my copy of production site which is on another server (‘https://myproductioncopy.com/‘). The same error is for copy of production and it’s only problem with this site on wp engine.

Have anyone idea what could be a reason of this, or how to find issue or to fix, anything, because I am without any idea.