폼메일 발송시 메일이 안오는 문제

<meta charset="utf-8">
<?php
if(isset($_POST['email'])) {


$email_to = "[email protected]";
$email_subject = "[폼메일] 문의사항입니다.";
$email_subject = '=?UTF-8?B?'.base64_encode($email_subject).'?=';



function died($error) {
// your error code can go here
echo "<script> alert('메일발송을 실패하였습니다.');";
echo "history.go(-1);";
echo "</script>";
die();
}

// validation expected data exists
if(!isset($_POST['first_name']) ||
!isset($_POST['email']) ||
!isset($_POST['telephone']) ||
!isset($_POST['comments'])) {
died('We are sorry, but there appears to be a problem with the form you submitted.');
}

$first_name = $_POST['first_name']; // required
$email_from = $_POST['email']; // required
$telephone = $_POST['telephone']; // not required
$comments = $_POST['comments']; // required

$error_message = "";
$email_exp = '/^[A-Za-z0-9._%-]+@[A-Za-z0-9.-]+.[A-Za-z]{2,4}$/';
if(!preg_match($email_exp,$email_from)) {
$error_message .= 'The Email Address you entered does not appear to be valid.<br />';
}

if(strlen($comments) < 2) {
$error_message .= 'The Comments you entered do not appear to be valid.<br />';
}
if(strlen($error_message) > 0) {
died($error_message);
}
$email_message = "";

function clean_string($string) {
$bad = array("content-type","bcc:","to:","cc:","href");
return str_replace($bad,"",$string);
}

$email_message .= "이름 : ".clean_string($first_name)."\n\n";
$email_message .= "이메일 : ".clean_string($email_from)."\n\n";
$email_message .= "연락처 : ".clean_string($telephone)."\n\n";
$email_message .= "문의사항 : ".clean_string($comments)."\n\n";


// create email headers
$headers = 'From: '.$email_from;
// 제목이 깨질경우 아래 캐릭터셋 적용

@mail($email_to, $email_subject, $email_message, $headers);
?>

<!-- include your own success html here -->

<script>
alert ("메일이 발송되었습니다.\n빠른 시일안에 답변드리겠습니다.");
location.href='/';
</script>

<?php
}
?>

폼메일 발송 부분입니다.