This Error event indicates that the DSProxy component of the Microsoft Exchange System Attendant service on the Exchange server failed to service a client request. This failure could be caused by issues ranging from failed network connectivity to permissions problems.

The following are the most probable causes of this event:

• The primary network adapter in a multi-homed domain controller may not have File and Printer Sharing for Microsoft Networks bound to it.
  
  
• The File Replication service may not have successfully replicated an updated security policy to one or more domain controllers.
  
  

To resolve this error, do one or more of the following:

• Change the binding order of the network adapters so that the adapter listed at the top of the Connections list has File and Printer Sharing for Microsoft Networks bound to it.
  
  
• Make sure that replication between domain controllers is occurring correctly.
  
  
• Resolve your issue by using self-support options, assisted support options, and other resources. You can access these resources from the Exchange Server Solutions Center. From this page, click Self-Support Options in the navigation pane to use self-help options. Self-help options include searching the Microsoft Knowledge Base, posting a question at the Exchange Server forums, and others. Alternatively, in the navigation pane, you can click Assisted Support Options to contact a Microsoft support professional. Because your organization may have a specific procedure for directly contacting Microsoft Technical Support, be sure to review your organization's guidelines first.
  
  

For more information about network issues and domain controllers, refer to Microsoft Windows documentation.

If you are not already doing so, consider running the Exchange tools created to help you analyze and troubleshoot your Exchange environment. These tools can help make sure that your configuration aligns with Microsoft best practices. They can also help you identify and resolve performance issues, improve mail flow, and better manage disaster recovery scenarios. To run these tools, go to the Toolbox node of the Exchange Management Console. To learn more about these tools, see Managing Tools in the Toolbox.