Google reCAPTCHA working on Local but not on my server - recaptcha

Question

I have a form which requires a google reCAPTCH to be ticked. It is working perfectly on Local but does not work when I put it on the development server. I have replaced the registered keys to the ones appointed to me by Google.
It keeps outputting the error message.
The method in my form is post.
I do not understand why it doesn't work. Can someone please help me?
Here is my code:
$secretKey = "#######";
$captcha = $_POST['g-recaptcha-response'];
$ip = $_SERVER['REMOTE_ADDR'];
$response=file_get_contents("https://www.google.com/recaptcha/api/siteverify?secret=".$secretKey."&response=".$captcha."&remoteip=".$ip);
$responseKeys = json_decode($response,true);
if(intval($responseKeys["success"]) !== 1) {
$throwErrorMessage = "You are a robot! ";
$throwError = 1;
$isvalid = False;
};

Answer 1

What version of ReCAPTCHA are you using? The docs on Google website here are pretty different than your code. In particular, you use the function file_get_contents while the documentation uses recaptcha_check_answer like in this example:
<?php
require_once('recaptchalib.php');
$privatekey = "your_private_key";
$resp = recaptcha_check_answer ($privatekey,
$_SERVER["REMOTE_ADDR"],
$_POST["recaptcha_challenge_field"],
$_POST["recaptcha_response_field"]);
if (!$resp->is_valid) {
// What happens when the CAPTCHA was entered incorrectly
die ("The reCAPTCHA wasn't entered correctly. Go back and try it again."."(reCAPTCHA said: " . $resp->error . ")");
} else {
// Your code here to handle a successful verification
}
?>
Can you post the error message?