The best place to start to attempt to identify the problem is to look at the configuration of the public virtual directory within your default Web site in Internet Information Server (IIS). In the Security tab, make note of any restrictions that are there, including IP address, SSL requirements and authentication methods. Compare these to the settings of your Exchange Server virtual directory and then report back to us for a follow-up.
Do you have comments on this Ask the Expert Q&A? Let us know.
Related information from SearchExchange.com:
Dig Deeper on Exchange Server setup and troubleshooting
Related Q&A from Bradley Dinerman
Find out how you can avoid DNS issues related to a Exchange 2003 server only collecting email from specific POP3 domains. Continue Reading
Are you having trouble with duplicate appointments in your Microsoft Outlook 2003 calendar? Learn what may cause this to happen. Continue Reading
Learn the best way to configure the default recipient policy in an Exchange 2003 test environment. Continue Reading