Hi CAS server : Exchange 2010 on Windows 2008 R2 64bit I am having OWA connection issue, try to browse the owa page in CAS server error : Request Url: https://127.0.0.1:443/owa/ User host address: 127.0.0.1 OWA version: 14.1.270.1 Exception Exception type: System.NullReferenceException Exception message: Object reference not set to an instance of an object. Call stack Microsoft.Exchange.Clients.Owa.Core.RequestDispatcher.GetUserIdentities(OwaContext owaContext, OwaIdentity& logonIdentity, OwaIdentity& mailboxIdentity, Boolean& isExplicitLogon, Boolean& isAlternateMailbox, ExchangePrincipal& logonExchangePrincipal) Microsoft.Exchange.Clients.Owa.Core.RequestDispatcher.InternalDispatchRequest(OwaContext owaContext) Microsoft.Exchange.Clients.Owa.Core.RequestDispatcher.DispatchRequest(OwaContext owaContext) Microsoft.Exchange.Clients.Owa.Core.OwaRequestEventInspector.OnPostAuthorizeRequest(Object sender, EventArgs e) System.Web.HttpApplication.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) Event log : Log Name: Application Source: Microsoft-Windows-IIS-W3SVC-WP Date: 4/7/2011 10:11:55 AM Event ID: 2280 Task Category: None Level: Error Keywords: Classic User: N/A Computer: MEXCHCAS01.domainname.grp Description: The Module DLL C:\Program Files\Microsoft\Exchange Server\V14\ClientAccess\Owa\auth\exppw.dll failed to load. The data is the error. Event Xml: <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event"> <System> <Provider Name="Microsoft-Windows-IIS-W3SVC-WP" Guid="{670080D9-742A-4187-8D16-41143D1290BD}" EventSourceName="W3SVC-WP" /> <EventID Qualifiers="49152">2280</EventID> <Version>0</Version> <Level>2</Level> <Task>0</Task> <Opcode>0</Opcode> <Keywords>0x80000000000000</Keywords> <TimeCreated SystemTime="2011-04-07T02:11:55.000000000Z" /> <EventRecordID>99632</EventRecordID> <Correlation /> <Execution ProcessID="0" ThreadID="0" /> <Channel>Application</Channel> <Computer>MEXCHCAS01</Computer> <Security /> </System> <EventData> <Data Name="ModuleDll">C:\Program Files\Microsoft\Exchange Server\V14\ClientAccess\Owa\auth\exppw.dll</Data> <Binary>05000000</Binary> </EventData> </Event> Have tried to restart the IIS services and server, but problem persist. Wondering if anyone can advice? thanks and regards Jinfa

Hi James and Anil Thanks for the reply. Apparently, I can now access the OWA via my CAS server's IIS. But the event is still there every other minute. I have tried to config the bitness = 64 according to this link http://www.jjclements.co.uk/2010/10/24/exchange-2010-sp1-issues/ but problem still persist. Btw, my EXPA report seems abit too big... do i paste the xml codes here? Please advice thanks and regards Jinfa

Hi Supa4 I just read your case. You can post error information of exbpa report. Can you post how do you fix owa exception? Why you get module error and owa works well… 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.

Has there been any resolution to this? I have the same issue. C:\Program Files\Microsoft\Exchange Server\V14\ClientAccess\Owa\auth\exppw.dll 05000000 The Module DLL C:\Program Files\Microsoft\Exchange Server\V14\ClientAccess\Owa\auth\exppw.dll failed to load. The data is the error. A listener channel for protocol 'http' in worker process '1080' serving application pool 'DefaultAppPool' reported a listener channel failure. The data field contains the error number. I have set bitness on exppw.dll and still get this error.