You receive an "Error 500" error message in Outlook Web Access after you install Exchange Server 2003 on a computer that is running Windows Server 2003

You install Microsoft Exchange Server 2003 on a computer that is running Microsoft Windows Server 2003. When you log on to Microsoft Outlook Web Access to obtain access to a mailbox on the server that is running Exchange Server 2003, a blank HTML page is displayed. Additionally, if you enabled the Show friendly HTTP error messages option in Microsoft Internet Explorer, you receive the following error message:

This issue occurs if you install and then remove Windows Server 2003 Service Pack 1 (SP1). When you install and then remove Windows Server 2003 SP1, the Internet Information Services (IIS) .dll files that are included with Windows Server 2003 SP1 are running on Windows Server 2003 without SP1 installed. The mismatched .dll files cause IIS to drop TCP connections. Therefore, the Outlook Web Access client cannot access the Exchange Server 2003 server.

To resolve this issue, use one of the following methods.

Method 1: Install Windows Server 2003 SP1

For more information about how to obtain Windows Server 2003 SP1, click the following article number to view the article in the Microsoft Knowledge Base:

Method 2: Remove and then reinstall IIS 6.0 and Exchange Server 2003

If Exchange Server 2003 Service Pack 1 (SP1) is installed on the computer, follow these steps:

Important For information about how to prevent data loss when you remove and then reinstall IIS 6.0 and Exchange Server 2003, click the following article number to view the article in the Microsoft Knowledge Base:

1. Remove and then reinstall IIS 6.0.
2. Remove and then reinstall Exchange Server 2003.
3. Apply hotfix 831464. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
   831464 FIX: IIS 6.0 compression corruption causes access violations
   Note You must restart the computer after you apply hotfix 831464.
4. Install Exchange Server 2003 SP1. For more information about how to obtain Exchange Server 2003 SP1, click the following article number to view the article in the Microsoft Knowledge Base:
   836993 How to obtain the latest service packs for Exchange Server 2003