Bad HELO – Host impersonating domain name

I’ve 2 DA servers: – web server, MTA is stopped, local mail transfer is off in DirectAdmin. – mail server (smtp/pop3/imap) – DNS (named) service IS disabled.

Domain is added on both servers. And now all works fine, but when I send e-mail using SMTP (mta server) from PHP script (on web), I got en error im exim (on mta): ( [] rejected EHLO or HELO Bad HELO – Host impersonating domain name []

The solution is to add this to config of phpmailer:
$mail->Hostname = "";
$mail->Helo = $mail->Hostname;

The problem is that a domain exist on both servers. PHP mailer by default use a _SERVER["SERVER_NAME"] as HELO.

How to fix a problem gloabally?

Thank you.