当我进入我的reCAPTCHA时，我发现它没有正确输入

Question

我创建了一个简单的联系表单，但在使用reCAPTCHA时，我得到了这样的答案： 未正确输入reCAPTCHA。回去再试一次。（reCAPTCHA说：wrong-captcha-sol） 这是我的代码：

<div id="contact-area">
        <form method="post" action="contactengine.php">
            <label for="Name">Name:</label>
            <input type="text" name="Name" id="Name" />

            <label for="Email">Email:</label>
            <input type="text" name="Email" id="Email" />

            <label for="Tel">Tel:</label>
            <input type="text" name="Tel" id="Tel" />

            <label for="Message">Message:</label><br />
            <textarea name="Message" rows="20" cols="20" id="Message"></textarea>

<div id="captcha-area">
<?php
                require_once('recaptchalib.php');
                $publickey = "XXX";
                $privatekey = "XXXX";
                # the response from reCAPTCHA
                $resp = null;
                # the error code from reCAPTCHA, if any
                $error = null;
                # are we submitting the page?
                if ($_POST["submit"]) {
                  $resp = recaptcha_check_answer ($privatekey,
                                                  $_SERVER["REMOTE_ADDR"],
                                                  $_POST["recaptcha_challenge_field"],
                                                  $_POST["recaptcha_response_field"]);
                  if ($resp->is_valid) {
                    echo "You got it!";
                    # in a real application, you should send an email, create an account, etc
                  } else {
                    # set the error code so that we can display it. You could also use
                    # die ("reCAPTCHA failed"), but using the error message is
                    # more user friendly
                    $error = $resp->error;
                  }
                }
                echo recaptcha_get_html($publickey, $error);
                ?>

            </div>
            <input type="submit" name="submit" value="Submit" class="submit-button" />
        </form>

contactengine.php：

<?php
require_once('recaptchalib.php');
$privatekey = "6Le16v8SAAAAAJuq96o2aA5N8xhklXpQbWR3bogG";
$resp = recaptcha_check_answer ($privatekey,
                                $_SERVER["REMOTE_ADDR"],
                                $_POST["recaptcha_challenge_field"],
                                $_POST["recaptcha_response_field"]);
if (!$resp->is_valid) {
  die ("The reCAPTCHA wasn't entered correctly. Go back and try it again." .
       "(reCAPTCHA said: " . $resp->error . ")");
}
$EmailFrom = "example@example.com";
$EmailTo = "marlenebrazier@gmail.com";
$Subject = "Nice & Simple Contact Form by CSS-Tricks";
$Name = Trim(stripslashes($_POST['Name'])); 
$City = Trim(stripslashes($_POST['City'])); 
$Email = Trim(stripslashes($_POST['Email'])); 
$Message = Trim(stripslashes($_POST['Message'])); 
// validation
$validationOK=true;
if (!$validationOK) {
  print "<meta http-equiv=\"refresh\" content=\"0;URL=error.htm\">";
  exit;
}
// prepare email body text
$Body = "";
$Body .= "Name: ";
$Body .= $Name;
$Body .= "\n";
$Body .= "City: ";
$Body .= $City;
$Body .= "\n";
$Body .= "Email: ";
$Body .= $Email;
$Body .= "\n";
$Body .= "Message: ";
$Body .= $Message;
$Body .= "\n";
// send email 
$success = mail($EmailTo, $Subject, $Body, "From: <$EmailFrom>");
// redirect to success page 
if ($success){
  print "<meta http-equiv=\"refresh\" content=\"0;URL=contactt``hanks.php\">";
}
else{
  print "<meta http-equiv=\"refresh\" content=\"0;URL=error.htm\">";
}
?>