[SOLVED] Email feature is not working Kindly help

<?php
         $to = "rakesh1084@gmail.com";
         $subject = "This is subject";         
         $message = "<b>This is HTML message.</b>";
         $message .= "<h1>This is headline.</h1>";
         $header = "From:rakesh1084@gmail.com \r\n";
         $header .= "Cc:rakesh1084@gmail.com \r\n";
         $header .= "MIME-Version: 1.0\r\n";
         $header .= "Content-type: text/html\r\n";         
         $retval = mail ($to,$subject,$message,$header);
    
         if( $retval == true ) {
            echo "Message sent successfully...";
         }else {
            echo "Message could not be sent...";
         }
      ?>

2017-01-19 21:12:27.980 ***** ERROR ***** ERROR *****
2017-01-19 21:12:27.983 ***** ERROR ***** on file 'C:\inetpub\wwwroot\projeqtor\external\PHPMailer\class.smtp.php' at line (286)
2017-01-19 21:12:27.986 ***** ERROR ***** cause = stream_socket_client(): unable to connect to localhost:25 (No connection could be made because the target machine actively refused it.
)
2017-01-19 21:12:27.988 ***** ERROR ***** Error sending mail
2017-01-19 21:12:27.991 ***** ERROR *****    SMTP Server : localhost
2017-01-19 21:12:27.993 ***** ERROR *****    SMTP Port : 25
2017-01-19 21:12:27.996 ***** ERROR *****    Mail stored in Database : #93
2017-01-19 21:12:27.998 ***** ERROR *****    PHPMail error : SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting
2017-01-19 21:12:28.000 ***** ERROR *****    PHPMail debug : 

$g_phpMailer_method = PHPMAILER_METHOD_SMTP;
$g_smtp_host = 'sm02.org.com';
$g_smtp_port = 25;
$g_smtp_username = 'userid';
$g_smtp_password = 'secret';
$g_enable_email_notification='ON';

// Mail transport available: "smtp", "sendmail", "mail" (PHP mail function), "postmark", "mailgun", "sendgrid"
define('MAIL_TRANSPORT', 'smtp');
// SMTP configuration to use when the "smtp" transport is chosen
define('MAIL_SMTP_HOSTNAME', 'sm02.org.com');
define('MAIL_SMTP_PORT', 25);
define('MAIL_SMTP_USERNAME', 'userid');
define('MAIL_SMTP_PASSWORD', 'secret);
define('MAIL_SMTP_ENCRYPTION', null); // Valid values are "null", "ssl" or "tls"