Php表单邮件无效

Question

在互联网上找到一个php表单。当我运行表单时，表单完美无缺，除了我没有收到地址上的邮件。这是邮件文件的完整代码（不包括带有运行Captcha的php代码的其他文件）

<?php 
$your_email ='fanchelsea06@gmail.com';

session_start();
$errors = '';
$name = '';
$visitor_email = '';
$user_message = '';

if(isset($_POST['submit']))
{

    $name = $_POST['name'];
    $visitor_email = $_POST['email'];
    $user_message = $_POST['message'];

    if(empty($name)||empty($visitor_email))
    {
        $errors .= "\n Name and Email are required fields. ";   
    }
    if(IsInjected($visitor_email))
    {
        $errors .= "\n Bad email value!";
    }
    if(empty($_SESSION['6_letters_code'] ) ||
      strcmp($_SESSION['6_letters_code'], $_POST['6_letters_code']) != 0)
    {
        $errors .= "\n The captcha code does not match!";
    }

    if(empty($errors))
    {
        //send the email
        $to = $your_email;
        $subject="New form submission";
        $from = $your_email;
        $ip = isset($_SERVER['REMOTE_ADDR']) ? $_SERVER['REMOTE_ADDR'] : '';

        $body = "A user  $name submitted the contact form:\n".
        "Name: $name\n".
        "Email: $visitor_email \n".
        "Message: \n ".
        "$user_message\n".
        "IP: $ip\n";    

        $headers = "From: $from \r\n";
        $headers .= "Reply-To: $visitor_email \r\n";

        mail($to, $subject, $body,$headers);

        header('Location: thank-you.html');
    }
}
function IsInjected($str)
{
  $injections = array('(\n+)',
              '(\r+)',
              '(\t+)',
              '(%0A+)',
              '(%0D+)',
              '(%08+)',
              '(%09+)'
              );
  $inject = join('|', $injections);
  $inject = "/$inject/i";
  if(preg_match($inject,$str))
    {
    return true;
  }
  else
    {
    return false;
  }
}

请建议使用替代代码。