Can't log into server from Project Pro 2003

[SizzleMaster]

I've never been able to log into my project server 2003 from project
professional running on my XP machine which is not a member of the domain
that the server runs on. I've tried both auth methods. I used to be able
to log in using the Project Server Administrator account but I've recently
rebuilt the project server and now get the error below. I'm running inside
of ISA with the firewall client installed. Get same error with the client
enabled or disabled. The PS URL is in my trusted sites and I have
everything enabled for the trusted sites security. What's going on? Any
help would be appreciated.

You are not authorized to view this page
You do not have permission to view this directory or page using the
credentials that you supplied because your Web browser is sending a
WWW-Authenticate header field that the Web server is not configured to
accept.

 

[SizzleMaster]

Thanks but that is checked. I can browse the server using the trusted URL
in IE but when I hit the Test Conection button after adding a project server
account in PP, I recieve the error below. This wasn't the case before.
What might have changed? Any other ideas?

Thaks again!