Has anyone encountered the following warnings and error? The warnings vary between event ID 5 and 6 until an error is generated with an event ID of 7. The errors come about every 5 minutes. A sample of each is below. It started yesterday in the afternoon. I can't think of any changes that could have been made. I restarted all web services and eventually rebooted. They persist. Event Type: Warning Event Source: MSExchange Web Services Event Category: Core Event ID: 6 Date: 12/19/2009 Time: 5:05:24 PM User: N/A Computer: CAS1 Description: Unable to send a notification for subscription HABkYy1jYXMxLmJvc3RvbnByb3BlcnRpZXMuY29tEAAAAJTMWGDbMvhOvs2P6CGieDg=. (Send attempts: 5) For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp. Event Type: Error Event Source: MSExchange Web Services Event Category: Core Event ID: 7 Date: 12/19/2009 Time: 5:06:40 PM User: N/A Computer: CAS1 Description: After 7 unsuccessful attempts to send a notification for subscription HABkYy1jYXMxLmJvc3RvbnByb3BlcnRpZXMuY29tEAAAAPQCTI/hbxVGnY2yTl5DBdU=, subscription has been removed. For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

Check for Mike Shen's comment on this http://social.technet.microsoft.com/Forums/en-US/exchangesvrgeneral/thread/ec50b24c-0073-4dee-b698-764bff0841e7 The event 5, 6, and 7 are basically event that telling us that a device/client is subscribing a server event, but when the server when to notify the client/device, the client is not there to respond to it, so the server threw and error and close the subscription. For your reference: http://social.technet.microsoft.com/Forums/en-US/exchangesvrdevelopment/thread/015cfdc6-8bde-4a78-93db-bb866a15f685/Raj