Hello all I am having a peculiar problem with an front end serverI can no longer access Outlook web access or get push mail,Once I browse to outlook web access form and enter user name and password I get an unspecified error pageThis works fine with the back end servers.Looking in the event viewer system log there is an Service control error Event id 7001The Microsoft Exchange Information Store service depends on the Microsoft Exchange System Attendant service which failed to start because of the following error: The operation completed successfully. The application log has many 2114 event idssource MSExchangeDSAccessProcess IISIPMB26D432B-1706-4107-8CBA-0121118E4D61 -AP "EXCHANGEAPPLICATIONPOOL (PID=3068). Topology Discovery failed, error 0x8007077f. OMA was still funtioning but i tried to recreate the virtual directories using this articlehttp://support.microsoft.com/?id=883380any sugestions in what to do next?Thanks in AdvanceJohn

Hi, Please check whether the below link can help you: http://support.microsoft.com/kb/919089/en-us Thanks Allen

Hi John, Just been reading your post - did you manage to resolve the errors that you were seeing. I am experiencing a similar sounding error - Over the last month I have been seeing errors on one NLB CA 2007 node. The node did work well and event log was free from errors. The node seems to loose the network, it pings but is not available through remote desktop. I have to gain access through the remote access card on which the console locks - I then have to power off and on through the remote access card. When I reboot it seems fine and works for a time but then it stops working and repeats the same errors in the event log - errors are below: Event Type: Error Event Source: MSExchange ADAccess Event Category: Topology Event ID: 2142 Date: 14/05/2009 Time: 02:12:47 User: N/A Computer: computername Description: Process IISIPMC03AD76C-E1F7-44C0-94C4- 9C7F90AFA8F3 -AP "MSEXCHANGEOWAAPPPOOL (PID=1676). Topology discovery failed, error 0x8007051f. For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp . Event Type: Error Event Source: MSExchange ADAccess Event Category: General Event ID: 2501 Date: 14/05/2009 Time: 02:09:15 User: N/A Computer: computername Description: Process MSEXCHANGEADTOPOLOGY (PID=1652). 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. For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp . Event Type: Error Event Source: Userenv Event Category: None Event ID: 1110 Date: 14/05/2009 Time: 01:52:15 User: NT AUTHORITY\SYSTEM Computer: computername Description: Attempt to determine whether user and machine accounts are in the same forest failed (There are currently no logon servers available to service the logon request. ). For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp . A few weeks back we did experience a time skew, and the errors seem to have occured since then. I have checked DNS and the records for the Exchange servers do exist. The server seems fine performance wise - not overworked but aswell as the errors we have seen some virtual memory errors - the server does have plenty of memory and a suitable paging file. If you have a solution or any tips that you may feel relevant then they would be most welcomed. Thanks Julie