Error message when you try to use the spelling checker in Outlook Web Access: "Your Exchange server is busy and can't check spelling at this time. Try again later"

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You go through a Microsoft Exchange Server 2007 server that is running the Client Access Server (CAS) role to accesses a mailbox that is hosted on a Microsoft Exchange Server 2003 server. If you try to use the spelling checker in Microsoft Office Outlook Web Access, you receive the following error message:
Your Exchange server is busy and can't check spelling at this time. Try again later.
This problem occurs if you belong to many secure groups that results in a large token. The spelling checker in Outlook Web Access for Exchange 2003 has an 8-kilobyte (KB) limit for all HTTP headers. When you go through an Exchange 2007 server that is running the CAS role to access the mailbox, the POST command fails if the Kerberos authorization header is larger than 8 KB.

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.


Because of file dependencies, this hotfix requires Microsoft Exchange Server 2003 Service Pack 2 to be installed on the server. For more information, 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

Restart requirement

You do not have to restart the computer after you apply this hotfix. However, the IIS Admin Service and all dependent services are automatically restarted when you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

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.
File nameFile versionFile sizeDateTime
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
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Article ID: 940011 - Last Review: 01/16/2015 02:29:56 - Revision: 1.3

Microsoft Exchange Server 2003 Standard Edition, Microsoft Exchange Server 2003 Enterprise Edition

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