I’m seeing some odd problems in Exchange 2007 and wondering if anyone has run across a similar issue. Lately my message queues occasionally back up, and have also noticed that the CAS-Hub server seems to be intermittently losing its connection to or Mailbox server (I pasted a few log entries from our CAS-Hub event logs below). In addition to this, some of our Outlook 2007 users are occasionally seeing “Cannot open this item. Network problems are preventing connection to Microsoft Exchange” errors throughout the day, as well as a few people with Outlook disconnect\reconnects. Our servers: Exchange 2007 SP1 rollup 8 Cas\Hub Server is running in VMware – Windows 2003 64 One SCC Mailbox cluster (physical hardware) running Windows 2003 64 So it almost seems like our mailbox is losing network connectivity for very short periods of time? I’ve done some checking and have found no noticeable problems so far on the mailbox server. I did get a few Test-ActivesyncConnectivity tests on the CAS-Hub server to fail when I noticed the queues backing up, but aside from those ‘disconnected’ times I don’t show any problems when I run them. These problems have happened multiple times today – no specific pattern. Things have been running pretty stable for the last year with this setup and no major changes were made. This problem popped up a few weeks ago but I wrongly assumed it was due to an archiving server (this was a test server that had been running a few months). I’ve also flipped cluster nodes to try to rule out a bad NIC\cable\port, but this has had no effect. Has anyone else run into this? I would have guessed that there are network problems or that the Mailbox server is dropping offline, but the fact that I have changed cluster nodes and still have the problem has me scratching my head. I think the problem has been happening pretty frequently, but that we are only seeing the worst effects during peak usage. Our servers are pretty underutilized – we have about 1400 users with mailboxes averaging 150 meg. I’m also wondering if I have a corrupt database somewhere (we have 4 mailbox and one public folder database). Any ideas? A few events from event log on the Cas\Hub... Event #1 on Cas-Hub server The connection between the Client Access server and Mailbox server "ourmailserver.ourmailserver.com" failed. If this event is logged infrequently or only during scheduled downtime for a Mailbox server, no user action is required. If this event occurs repeatedly, check network connectivity using PING or PingPath. Also, check connectivity using the Test-ActiveSyncConnectivity cmdlet. More information: Microsoft.Exchange.Data.Storage.ConnectionFailedTransientException: Could not get properties. ---> Microsoft.Mapi.MapiExceptionNetworkError: MapiExceptionNetworkError: Unable to get properties on object. (hr=0x80040115, ec=1702) Diagnostic context: Lid: 18969 EcDoRpcExt2 called [length=143] Lid: 32249 EcDoRpcExt2 exception [rpc_status=0x6A6 ][latency=0] Lid: 25913 Lid: 21817 ROP Failure: 0x80040115 Lid: 20385 Lid: 28577 StoreEc: 0x80040115 Lid: 32001 Lid: 29953 StoreEc: 0x80040115 at Microsoft.Mapi.MapiExceptionHelper.ThrowIfError(String message, Int32 hresult, Object objLastErrorInfo) at Microsoft.Mapi.MapiProp.GetProps(PropTag[] propTagsRequested) at Microsoft.Exchange.Data.Storage.MapiPropertyBag.GetProperties(IList`1 propertyDefinitions) --- End of inner exception stack trace --- at Microsoft.Exchange.Data.Storage.MapiPropertyBag.GetProperties(IList`1 propertyDefinitions) at Microsoft.Exchange.Data.Storage.StoreObjectPropertyBag.InternalLoad(PropertyDefinition[] properties, Boolean forceReload) at Microsoft.Exchange.Data.Storage.StoreObjectPropertyBag.Load(PropertyDefinition[] properties) at Microsoft.Exchange.Data.Storage.Folder.InternalBind[T](StoreSession storeSession, MapiPropertyBag mapiPropertyBag, StoreObjectId folderObjectId, Byte[] changeKey, PropertyDefinition[] propsToReturn) at Microsoft.Exchange.Data.Storage.Folder.InternalBind[T](StoreSession storeSession, StoreId folderId, PropertyDefinition[] propsToReturn) at Microsoft.Exchange.Data.Storage.SyncStateStorage.GetSyncFolderRoot(MailboxSession mailboxSession) at Microsoft.Exchange.Data.Storage.SyncStateStorage.Bind(MailboxSession mailboxSession, String protocol, String deviceType, String deviceId) at Microsoft.Exchange.AirSync.Command.OpenSyncStorage(String deviceType, String deviceID) at Microsoft.Exchange.AirSync.PingCommand.FolderChangedSinceLastSync(DPFolderInfo folder, MailboxGetItemEstimateCommand command, Collection collection, Boolean tryNullSync) at Microsoft.Exchange.AirSync.PingCommand.InternalConsume(Event evt) Event # 2 on Cas-Hub Exchange ActiveSync has encountered repeated failures when it tries to access data on Mailbox server [ourmailserver.ourmailserver.com]. Exchange ActiveSync will temporarily stop making Exchange ActiveSync requests to the Mailbox server. The process will be postponed for [60] seconds. This may be caused if the Mailbox server is overloaded. If this event is frequently logged, review the Application log for other events that could indicate the root cause of performance problems on the Mailbox server specified in the event description. Event#3 on Cas-Hub Exchange ActiveSync is ending its back-off from Exchange Mailbox server [ourmailserver.ourmailserver.com]. Exchange ActiveSync will retry Exchange ActiveSync requests to the Exchange Mailbox server. For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp. Desktops are occasionally showing this error in Outlook 2007 Cannot open this item. Network problems are preventing connection to Microsoft Exchange.

We had a similar problem which we resolve by building a new Hub role VM and off loading that function from the CA/HUB VM server. Looks like a over utilization problem after applying the latest rollup.