邮件php返回true，但不发送

Question

我下载了模板，不需要使用邮件。我读了一下，但是没用。

我不想使用来自服务器的邮件。我想用我的Yahoo邮件接收。

我发送..返回true ..，但是我的Yahoo收件箱未收到。

怎么了？

这是代码

<?php
// Check for empty fields
if(empty($_POST['name']) || empty($_POST['email']) || empty($_POST['phone']) || empty($_POST['message']) || !filter_var($_POST['email'], FILTER_VALIDATE_EMAIL)) {
  http_response_code(500);
  exit();
}

$name = strip_tags(htmlspecialchars($_POST['name']));
$email = strip_tags(htmlspecialchars($_POST['email']));
$phone = strip_tags(htmlspecialchars($_POST['phone']));
$message = strip_tags(htmlspecialchars($_POST['message']));

// Create the email and send the message
$to = "myemail@yahoo.com.br"; // Add your email address inbetween the "" replacing yourname@yourdomain.com - This is where the form will send a message to.
$subject = "Website Contact Form:  $name";
$body = "You have received a new message from your website contact form.\n\n"."Here are the details:\n\nName: $name\n\nEmail: $email\n\nPhone: $phone\n\nMessage:\n$message";
$header = "From: noreply@yourdomain.com\n"; // This is the email address the generated message will be from. We recommend using something like noreply@yourdomain.com.
$header .= "Reply-To: $email";  

if(!mail($to, $subject, $body, $header))
  http_response_code(500);
?>

感谢帮助