Unable to send mail via PHP mail function - php

Question

I've been trying to send mail through the contact form on my website. I've used the POST method and that has seemed to work for another one of my projects, but now I'm puzzled as to what the problem is within the code. I've literally copy-pasted the code and still seem to come across the error. Also is there a way in which the name of the sender is displayed rather than the gibberish that actually ends up showing?
//PHP CODE
<?php
function has_header_injection($str){
return preg_match("/[\r\n]", $str);
}
if(isset ($_POST['submit'])){
$fname = $_POST['fname'];
$lname = $_POST['lname'];
$email = $_POST['email'];
$msg = $_POST['msg'];
if(has_header_injection($name) || has_header_injection($email)){
die();
}
if(!$fname || !$lname || !$email || $msg){
echo '<h4> All fields required!</h4>';
exit;
}
$to = 'mymail8#gmail.com'; //FOR ELUCIDATION
$subject = $fname . $lname ."sent you via your contact form";
$message = "Name: ". $fname . $lname;
$message .= "Email: $email\r\n";
$message .= "Message:\r\n$msg";
$message = wordwrap($message, 100);
$headers = "MIME-Version: 1.0" . "\r\n";
$headers .= "Content-type:text/html;charset=UTF-8" . "\r\n";
$headers .= "From: $lname <$email>\r\n";
$headers .= "X-Priority: 1\r\n";
$headers .= "X-MSMail-Priority: High\r\n\r\n";
mail($to, $subject, $message, $headers);
}
else{
echo "failed to send mail!";
}
?>
//FORM (HTML)
<form action="mail-handler.php" class="msg" method="POST">
<div class="name">
<div class="fname">
<div>FIRST NAME</div>
<input type="text" placeholder="Enter your first name" id="fname" name="fname">
</div>
<div class="lname">
<div>LAST NAME</div>
<input type="text" placeholder="Enter your last name" id="lname" name="lname">
</div>
</div>
<div class="add-info">
<div class="mail">
<div>E-MAIL</div>
<input type="text" placeholder="Enter your email" id="mail" name="email">
</div>
<div class="phn">
<div>PHONE NUMBER</div>
<input type="text" placeholder="Enter your phone number" id="phn" name="phn">
</div>
</div>
<div class="msg-box">
<div>MESSAGE</div>
<input type="text" placeholder="Enter your Message" id="msg" name="msg" >
</div>
<button type="submit" id="sub" name="aubmit">Submit</button>
</form>