When sending mail through mail system function, mail won't be send because of '\n' not a '\r\n', this change in class.phpmailer.php resolved the problem

function MailSend($header, $body) {
$to = "";
for($i = 0; $i < count($this->to); $i++)
{
if($i != 0) { $to .= ", "; }
$to .= $this->to[$i][0];
}

$body =  str_replace("\n","\r\n",$body);                
     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
}

I've seen make_lf_crlf function but it doesn't work correctly.