The Client Access server “%1” attempted to proxy Outlook Web Access traffic for mailbox “%2”. This failed because no Client Access server with an Outlook Web Access virtual directory configured for Kerberos authentication could be found in the Active Directory site of the mailbox. The simplest way to configure an Outlook Web Access virtual directory for Kerberos authentication is to set it to use Integrated Windows authentication by using the Set-OwaVirtualDirectory cmdlet in the Exchange Management Shell, or by using the Exchange Management Console. If you already have a Client Access server deployed in the target Active Directory site with an Outlook Web Access virtual directory configured for Kerberos authentication, the proxying Client Access server may not be finding that target Client Access server because it does not have an internalUrl parameter configured. You can configure the internalUrl parameter for the Outlook Web Access virtual directory on the Client Access server in the target Active Directory site by using the Set-OwaVirtualDirectory cmdlet.

Details
Product: Exchange
Event ID: 41
Source: MSExchange OWA
Version: 8.0
Symbolic Name: ProxyErrorCouldNotFindCAS
Message: The Client Access server “%1” attempted to proxy Outlook Web Access traffic for mailbox “%2”. This failed because no Client Access server with an Outlook Web Access virtual directory configured for Kerberos authentication could be found in the Active Directory site of the mailbox. The simplest way to configure an Outlook Web Access virtual directory for Kerberos authentication is to set it to use Integrated Windows authentication by using the Set-OwaVirtualDirectory cmdlet in the Exchange Management Shell, or by using the Exchange Management Console. If you already have a Client Access server deployed in the target Active Directory site with an Outlook Web Access virtual directory configured for Kerberos authentication, the proxying Client Access server may not be finding that target Client Access server because it does not have an internalUrl parameter configured. You can configure the internalUrl parameter for the Outlook Web Access virtual directory on the Client Access server in the target Active Directory site by using the Set-OwaVirtualDirectory cmdlet.
   
Explanation

This Error event indicates that the computer that is running the Client Access server role could not determine whether the Microsoft Office Outlook Web Access request should be processed by the local Client Access server, or if it should be redirected to another Client Access server that is located in a different Active Directory site. Therefore, the user who owns the mailbox specified in the event description cannot access their mailbox through Outlook Web Access. This event may occur if the settings for the Outlook Web Access virtual directory are configured incorrectly.

For more information about Outlook Web Access proxying and redirection, see Understanding Proxying and Redirection.

   
User Action

To resolve this error, take one or more of these steps:

  • Make sure that the msExchInternalHostName (Internal URL) attribute of the Outlook Web Access virtual directory exists and it matches the fully qualified domain name (FQDN) of the Client Access server.

  • Make sure that the Client Access server that receives the proxy request has Integrated Windows authentication enabled on the Outlook Web Access virtual directory.

For information about how to configure Integrated Windows authentication for Outlook Web Access, see How to Configure Integrated Windows Authentication.

For information about how to modify the properties of Outlook Web Access virtual directories using the Set-OwaVirtualDirectory cmdlet, see Set-OwaVirtualDirectory.

If you are not already doing so, consider running the tools that Microsoft Exchange offers to help administrators analyze and troubleshoot their Exchange environment. These tools can help you make sure that your configuration is in line with Microsoft best practices. They can also help you identify and resolve performance issues, improve mail flow, and better manage disaster recovery scenarios. Go to the Toolbox node of the Exchange Management Console to run these tools now. For more information about these tools, see Toolbox in the Exchange Server 2007 Help.

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