PHPMailer error php_network_getaddresses: getaddrinfo failed: Name or service not known

i create code for send email using php mailer and its work in localhost but when i run on live server show error bellow :

2020-11-16 07:45:03 SMTP ERROR: Failed to connect to server: php_network_getaddresses: getaddrinfo failed: Name or service not known (0) 2020-11-16 07:45:03 SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting Message could not be sent.Mailer Error: SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting

sendmail php code :

<?php
/**
 * This example shows sending a message using a local sendmail binary.
 */

require 'PHPMailer/PHPMailerAutoload.php';

$mail = new PHPMailer();
$mail->SMTPDebug = 2;
$mail->isSMTP();
$mail->Host = 'mail.domain.co.id';
$mail->SMTPAuth = true;
$mail->Username = 'notreply@domain.co.id'; 
$mail->Password = 'XXXXXXXXXX'; 
$mail->SMTPSecure = 'tls';
$mail->Port = 587;

$mail->setFrom('notreply@domain.co.id');
$mail->addReplyTo('notreply@domain.co.id');
$mail->addAddress('myemail@domain.co.id'); 

$mail->Subject = 'Test Email via Mailtrap SMTP using PHPMailer';
$mail->isHTML(true);
$mailContent = "<h1>Send HTML Email using SMTP in PHP</h1>
                <p>This is a test email I'm sending using SMTP mail server with PHPMailer.</p>";
$mail->Body = $mailContent;
if($mail->send()){
    echo 'Message has been sent';
}else{
    echo 'Message could not be sent.';
    echo 'Mailer Error: ' . $mail->ErrorInfo;
}

now im running in ubuntu server 12.04 LTS, is there any misconfiguration in my server?