WE had a problem with our exchagne 2007 server this morning, The memory was running extreemly high and mail was just sitting in the queue. The event logs tell me
The execution time of agent 'ExclaimerRoutingAgent' exceeded 300000 (milliseconds) while handling event 'OnSubmittedMessage'. This is an unusual amount of time for an agent to process a single event. However, Transport will continue processing this message.
Process MSEXCHANGEADTOPOLOGY (PID=4272). The site monitor API was unable to verify the site name for this Exchange computer - Call=DsGetSiteNameW Error code=800703e5. Make sure that Exchange server is correctly registered on the DNS server.
A reboot fixed the issue -but as to what caused it and how to prevent it happening again