This Error event indicates that the Microsoft Exchange Autodiscover service is unable to process requests from the Outlook or mobile clients because the Outlook or mobile provider file was unavailable in the Autodiscover virtual directory configuration. Therefore, Outlook or mobile clients will be unable to access Exchange services such as the Availability service. This event may be caused because the Autodiscover service is not configured correctly on the Microsoft Exchange Client Access server.

To resolve this error, do the following on the Exchange Client Access Server.

• Check to see whether Autodiscover service is configured correctly.
  
  
• Install or reinstall the provider file, Microsoft.Exchange.Autodiscover.dll in this path: D:\Program Files\Microsoft\Exchange Server\ClientAccess\Autodiscover\bin.
  
  
• If these options do not help in resolving the issue, contact Microsoft Product Support Services. For more information, visit the Contact Us page of the Microsoft Help and Support Web site.
  
  
• 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.
  
  
• 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 the Autodiscover service, see Managing the Autodiscover Service.

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.