Send email through php using mailer class get spam emails - php

Question

I am working to send email via the PHP Mailer class. I tried many times but I'm getting spam email every time. I want to use it for whatuser. I am using the PHP Mailer class and get spam emails. Please help, my code is the following:
require_once("PHPMailer-final/class.phpmailer.php");
$admin_email="support#example.com";
$admin_email_caption="example.com";
$mail = new PHPMailer();
$mail->IsSMTP();
$mail->Host = "mail.example.com"; // SMTP servers
$mail->Port = 26;
$mail->SMTPAuth = true; // turn on SMTP authentication
$mail->Mailer = "smtp";
$mail->Username = "support#example.com"; // SMTP username
$mail->Password = "123456789"; // SMTP password
$subject=$subject_mem;
$cs_email=$to_mem;
$body_admin = $body_mem;
$headers ="From:".$admin_email_caption."<".$admin_email.">\nReply-To:".$admin_email."\nContent-Type:text/html";
$mail->From = $admin_email;
$mail->FromName = $admin_email_caption;
$mail->AddReplyTo($admin_email);
$mail->IsHTML(true);
$mail->Subject = $subject;
$mail->Body = $body_admin;
$mail->AltBody = "This is alt body.";
$mail->AddAddress($cs_email);
if(!$mail->Send())
#mail($cs_email,$subject,$body_admin,$headers) or die("not send");
//echo $cs_email."<br>";
$mail->ClearAddresses();
$mail->ClearAttachments();
$mail=NULL;

Answer 1

You should check your SMTP configurations.
Maybe SMTP configuration is not correct. For this reason your mail() function is working. And mail() function have some missing headers. Example charset. Missing or invalid header is another reason for getting mail in spam
Here is the details about PHPMailer Configurations
Uncomment the line //$mail->SMTPDebug = 3; for Debugging your SMTP configurations