您好，我有一个我制作的表单，它可以在本地计算机上运行，但不会在实时服务器上运行get\\u file\\u内容，因为它在响应中返回NULL？

形式：

 <form name="contactUS" action="<?php echo get_template_directory_uri(); ?>/mail/contact-us-mail-recaptcha.php" method="post">

<input name="name" type="text" placeholder="Name">
<input name="email" type="email" placeholder="Email">
<input name="message" type="textarea" placeholder="Please describe your project and the work to be done?">
<div class="g-recaptcha" data-sitekey="<site key>"></div>
<button type="submit" class="nsc-button">Submit</button>
</form>

<?php

$recaptcha_secret = \'<secret key>\';
$ip = $_SERVER[\'REMOTE_ADDR\'];
$captchaResponse = $_POST[\'g-recaptcha-response\'];

$response = file_get_contents("https://www.google.com/recaptcha/api/siteverify?secret=".$recaptcha_secret."&response=".$captchaResponse); 

$result = json_decode($response, true);

if($result == true){

//do success
}else {

    var_dump(\'ip:\' . $ip);
    var_dump(\'captchaResponse:\' . $captchaResponse);
    var_dump(\'response:\' . $response);
    var_dump(\'result:\' . $result);
    exit;

}