|Message:||Process %1: Unable to logon as network service context for proxying requests. Cross-site and cross-forests requests could fail because of this. Exception is %2.|
This Error event indicates that the Microsoft® Exchange Availability service did not logon as a network service. The Exchange Availability service retrieves the Schedule+ Free Busy and Out-Of-Office (OOF) data for a set of mailboxes residing on a computer that is running Exchange Server 2007. When the Exchange Availability service cannot directly connect to a mailbox that resides in a remote Active Directory directory service forest, it sends a proxy Web request to another instance of the Exchange Availability service that is running in the remote Active Directory forest by using Kerberos authentication. If Kerberos authentication fails, Network LAN Manager (NTLM) authentication is used. Under NTLM authentication, the Web request for a cross-site or cross-forest Exchange Availability service that is running under the context of a local computer uses an Anonymous user account.
The cross-site or cross-forest Availability service cannot authenticate an incoming Web request that uses an Anonymous user account. Therefore, the cross-site or cross-forest Availability service must impersonate the network service context. This means that even under NTLM authentication, the Web request for cross-site or cross-forest Exchange Availability service uses a local computer account. This event is logged when the Exchange Availability service does not create the network service authentication context.
To resolve this error, contact Microsoft Product Support Services. For more information, visit the Microsoft Help and Support Web site.
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.