未为 SMTP 电子邮件正确设置联系表单 PHP 文件且未发送

Question

I've set up an email form on my site, added the php file, but it won't send the form to my email address. I contacted my webhost and they replied with "You would need to use a script which supports SMTP for sending not sendmail() which is what the current script is using". What does this mean? Have I set up my php file wrong? I've included my php file below. The form is currently hosted here http://www.rockclick.co.uk/contact.htm

<script><?php
$name = $_POST['name'];
$email = $_POST['email'];
$message = $_POST['message'];
$subject = $_POST['subject'];
header('Content-Type: application/json');
if ($name === ''){
print json_encode(array('message' => 'Name cannot be empty', 'code' =>    0));
exit();
}
if ($email === ''){
print json_encode(array('message' => 'Email cannot be empty', 'code' =>   0));
exit();
} else {
if (!filter_var($email, FILTER_VALIDATE_EMAIL)){
print json_encode(array('message' => 'Email format invalid.', 'code' => 0));
exit();
}
}
if ($subject === ''){
print json_encode(array('message' => 'Subject cannot be empty', 'code' => 0));
exit();
}
if ($message === ''){
print json_encode(array('message' => 'Message cannot be empty', 'code'   => 0));
exit();
}
$content="From: $name \nEmail: $email \nMessage: $message";
$recipient = "enquiries@rockclick.co.uk";
$mailheader = "From: $email \r\n";
mail($recipient, $subject, $content, $mailheader) or die("Error!");
print json_encode(array('message' => 'Email successfully sent!', 'code'   => 1));
exit();
?></script>

Answer 1

I wasn't able to get this to work in the end so gave up and removed the form completely. It appears my web hosting doesn't support email forms. If anyone has a working email form which sends an email to a gmail address then please feel free to post it here! I googled and have literally spent all day on it and it's beaten me.