In the Admin Control Panel, if you set Use SMTP To Send E-mail to Yes, then a typo that exists in many PHP files causes errors when trying to send emails.
The typo occurs in:
$smtp_svr = $_SERVER["SERVER_NAME"];
if ($smtp_srv == 'localhost' || $smtp_svr == '127.0.0.1') {
$smtp_srv = 'FUDforum SMTP server';
}
$this->wts(($es ? 'EHLO ' : 'HELO ').$smtp_srv);
Notice that it defines $smtp_svr but tries to use $smtp_srv 3 times.
In my environment, I changed them all to $smtp_srv. And this problem exists in many files, including email.php, pmsg.php, post.php, etc.