XFOR: Err Msg: The Microsoft Exchange Server is Down (165712)

SYMPTOMS

When you attempt to connect to an Exchange Server version 5.0 mailbox from an Internet browser, you may get the error message:

Sorry! The Microsoft Exchange Server is down or the HTTP Service has been disabled by an administrator. Please try your request again later.

This error message may occur even though the Exchange Server has been properly configured to receive browser requests for mail delivery and the HTTP Service has not been disabled.

CAUSE

This problem has been seen to occur when Allow Anonymous Access is enabled on the Service tab of the Properties Dialog Box for the WWW Service in the Microsoft Internet Service Manager for Microsoft Internet Information Server (IIS). This problem has also been reported to occur if the LDAP protocol has been disabled for the Exchange Server that you are attempting to connect to.

WORKAROUND

It is sometimes possible to workaround this problem by following these steps:

Install an Exchange Client and create a profile on the computer that is running IIS and the Microsoft Exchange Server Active Server components.
Deselect the Allow Anonymous Access option for the WWW Service in IIS.
Stop the IIS services and then the Exchange Services.
Start the Exchange Services and then the IIS services. You can also restart the entire computer instead of performing steps 2 and 3.
Log into the Exchange Server via the web as an authenticated user.
At this point you can enable Allow Anonymous Access again.

STATUS

Microsoft has confirmed this to be a problem in Microsoft Exchange Server, version 5.0. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.