Exchange 2007 deployed across multiple Active Directory sites. Each CAS server in a remote site generates a 4002 applog error at approx. 20 minute intervals. The source is MSExchange Availability, and the description suggests we don't have an availabilty service in each site. I think that we do. This occurs on our field sites, but not on the CAS servers in our primary site. I'm not finding much info on this. Anyone?Ted

Hello,Would you confirm the following.Enabled Integrated Windows authentication (NTLM) on the /ews virtual directory on on CAS on both the sites?Arun Kumar | MCSE - 2K3 + Messaging | ITIL-F V3

Ted,The only document on Microsof TechNet I can link you related to your issue is http://www.microsoft.com/technet/support/ee/transform.aspx?ProdName=Exchange&ProdVer=8.0&EvtID=4002&EvtSrc=MSExchange+Availability&LCID=1033Follow the article and observer other errors those will be logged in your Application Log. Most of the times the information in event logs should point you to the correct resolution. For further reference you can also read at http://technet.microsoft.com/en-us/library/bb218238.aspxMMilind Naphade | MCTS:M | http://www.msexchangegeek.com

Any update on this?Arun Kumar | MCSE - 2K3 + Messaging | ITIL-F V3

Hi Ted, Would you please post the entire 4002 event here for further check? I would like to explain that the issue occurs if the server named in the "URL =" portion of the event cannot be located at the other Active Directory site. Either there are network connection problems or DNS issues preventing the other Client Access Server from being found on the network. Therefore, I suggest you ping the server by name from the local client access server your user is logging into to see their mailbox. f you do not receive a response you must check DNS to ensure proper configuration for the client access server at the other active directory site. If DNS seems to be in good order you might also have to check cross site network connectivity. More Information: When Outlook Web Access attempts to obtain availability information from a user's mailbox which resides at another active directory site, the InternalUrl of the EWS virtual directory of the client access server is used so the local client access server knows what url to use to perform the availability service call. You can check this url by running the following cmdlet: Get-WebServicesVirtualDirectory -Server <NameOfCrossSiteServer> | fl server,*url* If this entry is incorrect for some reason you can change it by running the following cmdlet: Set-WebServicesVirtualDirectory -Identity "<NameOfCrossSiteServer>\EWS (Default Web Site)" -InternalUrl https://<CorrectServerNameFQDN>/ews/exchange.asmx Mike

Connectivity looks to be okay. It looks like a cross site permissions issue. Within the 4002 event I find "The request failed with HTTP status 401: Unauthorized"

Hello Ted,Did you tried my suggestion mentioned earlier in my post?Arun Kumar | MCSE - 2K3 + Messaging | ITIL-F V3

Any update yet?Arun Kumar | MCSE - 2K3 + Messaging | ITIL-F V3

Hi Ted, I agree with Arun that we need to have Integrated Windows authentication (NTLM) enabled on the EWS virtual directory on the CAS server which indicated the server named in the "URL =" portion of the event Would you please also let me know whether "URL =" portion in all the Event 4002 indicated the same server? If yes, please post an example Event 4002 here Mike

This can happen when the WebServicesVirtualDirectory is pointing at the hostname of an individual server and not the CAS array. Please see this blog post for the resolution: http://clintboessen.blogspot.com/2011/02/eventid-4002-msexchangeavailability.htmlClint Boessen MVP - Exchange Server, MCSE, MCITPx4, Dip Network Engineering Perth, Western Australia Blog: http://clintboessen.blogspot.com/ Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.