Error message when you log on to Outlook Web Access on an Exchange Server 2003 front-end server: "401"

When you log on to Microsoft Outlook Web Access on a Microsoft Exchange Server 2003 front-end server, you receive a 401 error message.

This issue may occur when the back-end server name on which the mailbox resides is not in the Exprox cache on the Exchange Server 2003 front-end server.

By default, the Exprox cache on the Exchange Server 2003 front-end server holds the information for the Exchange Server 2003 back-end server. When the Exchange 2003 front-end server builds the Exprox cache, it uses the Directory Service Access (DSAccess) process to build a list of objects that has the msExchPrivateMDB attribute or the msExchPublicMDB attribute. If the value of the msExchPrivateMDB attribute is more than one thousand, the Exprox cache may not be completed during the DSAccess process.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

Because of file dependencies, this hotfix requires Microsoft Exchange Server 2003 Service Pack 2 (SP2).

Restart requirement

You must restart the computer after you apply this software update.

Hotfix replacement information

This hotfix does not replace any other software updates.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

For more information about the Microsoft Exchange Server 2003 Service Pack 1 version of this fix, click the following article number to view the article in the Microsoft Knowledge Base: For more information, click the following article number to view the article in the Microsoft Knowledge Base:For more information, click the following article number to view the article in the Microsoft Knowledge Base: