[Resolved] Windows IIS 6 + Mail()

[Erkilite]

We use a Windows 2003 Small Business Server with IIS 6, PHP 4.3.6, and Exchange.

When I try to send an email with PHP I get this message.

Warning: mail(): SMTP server response: 454 5.7.3 Client does not have permission to submit mail to this server.

Any ideas?

Figured it out.

Need to allow anonymous access in Exchange.