PHP SMTP mail hakkında yardım

<?php 
  session_cache_limiter('nocache'); 
  header('Expires: ' . gmdate('r', 0)); 
   
  header('Content-type: application/json'); 
   
  require 'php-mailer/class.phpmailer.php'; 
   
  // Your email address 
  $to = 'you@domain.com'; 
   
  $subject = $_POST['subject']; 
   
  if($to) { 
   
  	$name = $_POST['name']; 
  	$email = $_POST['email']; 
  	 
  	$fields = array( 
  		0 => array( 
  			'text' => 'Name', 
  			'val' => $_POST['name'] 
  		), 
  		1 => array( 
  			'text' => 'Email address', 
  			'val' => $_POST['email'] 
  		), 
  		2 => array( 
  			'text' => 'Message', 
  			'val' => $_POST['message'] 
  		) 
  	); 
  	 
  	$message = ""; 
  	 
  	foreach($fields as $field) { 
  		$message .= $field['text'].": " . htmlspecialchars($field['val'], ENT_QUOTES) . "<br>\n"; 
  	} 
  	 
  	$mail = new PHPMailer; 
   
  	$mail->IsSMTP();                                      // Set mailer to use SMTP 
  	 
  	// Optional Settings 
  	//$mail->Host = 'mail.yourserver.com';				  // Specify main and backup server 
  	//$mail->SMTPAuth = true;                             // Enable SMTP authentication 
  	//$mail->Username = 'username';             		  // SMTP username 
  	//$mail->Password = 'secret';                         // SMTP password 
  	//$mail->SMTPSecure = 'tls';                          // Enable encryption, 'ssl' also accepted 
   
  	$mail->From = $email; 
  	$mail->FromName = $_POST['name']; 
  	$mail->AddAddress($to);								  // Add a recipient 
  	$mail->AddReplyTo($email, $name); 
   
  	$mail->IsHTML(true);                                  // Set email format to HTML 
  	 
  	$mail->CharSet = 'UTF-8'; 
   
  	$mail->Subject = $subject; 
  	$mail->Body    = $message; 
   
  	if(!$mail->Send()) { 
  	   $arrResult = array ('response'=>'error'); 
  	} 
   
  	$arrResult = array ('response'=>'success'); 
   
  	echo json_encode($arrResult); 
  	 
  } else { 
   
  	$arrResult = array ('response'=>'error'); 
  	echo json_encode($arrResult); 
   
  } 
  ?>