PHPMailer在发送邮件时遇到问题

Question

I have placed the code of the PHPMailer in the file where I want to sent the mail but the mail is not delivered. I tried the ordinary mail() method but both sends the message but the message is not delivered. Can this be the issue with host service??

  include('PHPMailer-master/PHPMailerAutoload.php');
  $mail = new PHPMailer;
  // Set PHPMailer to use the sendmail transport
   $mail->isSendmail();
  //Set who the message is to be sent from
  $mail->setFrom('from@example.com', 'First Last');
  //Set an alternative reply-to address
   $mail->addReplyTo('replyto@example.com', 'First Last');
  //Set who the message is to be sent to
  $mail->addAddress( $_POST['RequestedEmail'], 'John Doe');
  //Set the subject line
  $mail->Subject = 'PHPMailer sendmail test';
  //Read an HTML message body from an external file, convert referenced  images to embedded,
 //convert HTML into a basic plain-text alternative body
 $mail->msgHTML("");
 //Replace the plain text body with one created manually
 $mail->AltBody = 'This is a plain-text message body';
  //send the message, check for errors
  if (!$mail->send()) {
  echo "Mailer Error: " . $mail->ErrorInfo;
  } else {
  echo "Message sent!";
}

Note: New to php

Answer 1

I tried both the mail() native function of the php and phpmailer. Both said that mail was sent and successful message appeared but the message was not delivered. I asked the technicians on the hosting server and they replied that spam blocker has blocked the messages. So they are asking for the contents and headers of the messages to confirm it was clear and to unblock the it from spamer. :)