This Warning event indicates that there is no suitable Active Directory server available to read the configuration data for the object specified in the event description. The Microsoft Exchange File Distribution service must read the configuration data from Active Directory to distribute offline address book (OAB) and custom Unified Messaging prompts.

This event may occur because of intermittent network issues.

If this Warning event frequently occurs, follow these steps:

• Use the Ping or PathPing command-line tools to test basic connectivity with the domain controller. Use Ping to isolate network hardware problems and incompatible configurations. Use PathPing to detect packet loss over multiple-hop trips. For more information, see Microsoft Knowledge Base article 325487, How to troubleshoot network connectivity problems.
  
  
• Run the Dcdiag command line tool to test domain controller health. To do this, run dcdiag /s:<Domain Controller Name> at a command prompt on the Exchange server. Use the output of Dcdiag to discover the root cause of any failures or warnings that it reports. For more information, see DCDIAG.
  
  
• Review the Application log and System log on your Exchange 2010 servers for related events. For example, events that occur immediately before and after this event may provide more information about the root cause of this error.
  
  
• To review detailed information about the cause of this alert, use the Operations Console in Operations Manager. For more information, see the introduction to this topic.
  
  
• 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.
  
  

This Warning event may be ignored if it occurred during known network issues.

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.