I suppose it is not an NT machine ?

Topanga wrote:

I suppose it is not an NT machine ?

It is a Windows 2003 server.

I was able to send an email via CDO (asp script) and it worked fine, so SMTP seems to be running properly.

I also checked the php.ini file and it *seems* to be OK.

Any other ideas, suggestions, etc???

OK. It's working now. Here's what I did - for any other user that's run into the same issue with an Windows 2003 Server.

The source of the problem ended up being with the SMTP relay NOT allowing the emails to be sent outside of the server. Since my server is on a (decently secure) Intranet, I basically opened it up to relay any email on to the (WAN) domain that I specified.

How: Start->Run->inetmgr
*Expand Servername
*Right-click on Default SMTP Virtual Server, select Properties
*On the Access tab, click the Relay and ensure that everything's allowed (this is probably a bad idea for an internet server)
*On the Access tab, double-check the Connection settings (click the Connection button and review the screen)
*On the Delivery tab, click the Advanced button and ensure that the fully qualified domain name is set properly. As my server will only be used by users within the same domain, I changed the property FROM the server name TO the domain name.
*On the security tab, I added the IUSR and the IWAM to the list of authorized users.

Like I mentioned, some of this is probably overkill or insecure. I'd welcome specific feedback.

What a relief to finally get this working!