|Message:||The Microsoft Exchange Mail Submission Service is currently unable to contact any Hub Transport servers in the local Active Directory site. The servers may be too busy to accept new connections at this time.|
This Warning event indicates that the computer that is running the Mailbox server role cannot submit messages to a computer that is running the Microsoft® Exchange Server 2007 Hub Transport server role. Additionally, there are Hub Transport servers in the same Active Directory® directory service site as the Mailbox server that can respond to the request. This event may occur if any of the following conditions is true:
In Exchange 2007, a new notification service called the Microsoft Exchange Mail Submission service runs on the mailbox server and notifies an available Hub Transport server in the same Active Directory site in which the service is running that messages are available for retrieval from a sender’s Outbox. The Microsoft Exchange Mail Submission service tries to distribute message submissions equally across all available Hub Transport servers that are available in the same Active Directory site in which the service is running.
The Microsoft Exchange Mail Submission service obtains a list of Hub Transport servers in the same Active Directory site as the mailbox from which a Store driver retrieves messages. A round-robin process determines which bridgehead server is notified. The store driver on the Hub Transport server that is notified retrieves the message and adds the message to the transport pipeline by putting it in the Submission queue on the Hub Transport server that was notified. If no bridgehead servers are available, messages cannot be added to the transport pipeline.
For more information, see Transport Architecture.
To resolve this warning, follow one or more of these steps:
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.