I am trying to send a email from my site, but I receive an error:

PHP Warning:  mail(): SMTP server response: 550 <test@gmail.com> No such user here in verificaSenha.php on line 15

My code is:

ini_set('SMTP', 'webmail.grupo360web.com.br');
ini_set('smtp_port', 25);
ini_set('sendmail_from', 'test@grupo360web.com.br');

$to = 'test@gmail.com';
$subject = 'test';
$message = 'test';
$headers = 'From: Test <test@grupo360web.com.br>' . "rn" .
'Reply-To: test@grupo360web.com.br' . "rn" .
'X-Mailer: PHP/' . phpversion();

$email = mail($to, $subject, $message, $headers);

if ($email){
echo 'ok';
}else{
echo 'no';
}