Hey guys, I'm using recaptcha and I've got a problem, when a user clicks the signup button it redirects him to the sign up verification page, and here is the code, found on the very top of the web code, that checks the recaptcha entered data.

<?php
require_once('recaptchalib.php');
$privatekey = "***";
$resp = recaptcha_check_answer ($privatekey,
$_SERVER["REMOTE_ADDR"],
$_POST["recaptcha_challenge_field"],
$_POST["recaptcha_response_field"]);
if (!$resp->is_valid) {

header('location: signup.php');

}
?>

But it seems whatever I type in in the recaptcha box, be it right or wrong, I get redirected to the signup.php page.

Here is the recaptcha code in the signup.php page:

  <?php
    ini_set('display_errors', 'On');
    error_reporting(E_ALL | E_STRICT);
      require_once('recaptchalib.php');
      $publickey = "***"; 
      echo recaptcha_get_html($publickey);
      ?>