Consider the following scenario:

  • You use Outlook Web App (OWA) to log on to a Microsoft Exchange Server 2010 mailbox.

  • You try to perform one of the following operations:

    • Delete an email message.

    • Mark an email message as read or unread.

    • Right-click a folder, and then click Empty Folder.

    • Upload an attachment.

In this scenario, you may receive one of the following error messages:

  • Error message 1:

    An unexpected error occurred and your request couldn't be handled.

  • Error message 2:

    The action you tried to perform couldn't be completed because there's a configuration problem on the server. If the problem continues, contact your helpdesk.

Additionally, the following events are logged in the Application log on the Client Access server:


The issue occurs when the Internet Information Services (IIS) website that hosts the Exchange Web Services (EWS) virtual directory contains a site binding that binds to an IPv6 address.

Note It is a known issue that this configuration may cause an exception .


To resolve this issue, install the hotfix that is described in Knowledge Base (KB) article 981667. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

981667 FIX: An exception occurs when a WCF client sends a request to a .NET Framework 3.5-based WCF service that uses an IPv6 address for the binding


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

More Information

For more information about EWS, visit the following Microsoft website:

General information about EWS

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