Domain Administrator didn't have any issues accessing emails via OWA. I assigned full mailbox rights to domain admin, then took them away, which broke OWA access for Admin account, however accessing admin's mailbox via outlook is not a problem. Request Url: https://server/owa/default.aspx User host address: 192.168.11.115 Exception Exception type: Microsoft.Exchange.Data.Storage.ConnectionFailedTransientException Exception message: Cannot open mailbox /o=First Organization/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=Administrator. Call stack Microsoft.Exchange.Data.Storage.ConnectionCachePool.OpenMailbox(String serverDn, String userDn, String mailboxDn, Guid mailboxGuid, Guid mdbGuid, Object identity, ConnectFlag connectFlag, OpenStoreFlag openStoreFlag, CultureInfo cultureInfo, String clientInfoString, Boolean secondTry) Microsoft.Exchange.Data.Storage.ConnectionCachePool.OpenMailbox(String serverDn, String userDn, String mailboxDn, Guid mailboxGuid, Guid mdbGuid, Object identity, ConnectFlag connectFlag, OpenStoreFlag openStoreFlag, CultureInfo cultureInfo, String clientInfoString, Boolean secondTry) Microsoft.Exchange.Data.Storage.ConnectionCachePool.OpenMailbox(String serverDn, String userDn, String mailboxDn, Guid mailboxGuid, Guid mdbGuid, Object identity, ConnectFlag connectFlag, OpenStoreFlag openStoreFlag, CultureInfo cultureInfo, String clientInfoString) Microsoft.Exchange.Data.Storage.MailboxSession.Initialize(LogonType logonType, ExchangePrincipal owner, DelegateLogonUser delegateUser, Object identity, OpenMailboxSessionFlags flags) Microsoft.Exchange.Data.Storage.MailboxSession.CreateMailboxSession(LogonType logonType, ExchangePrincipal owner, DelegateLogonUser delegateUser, Object identity, OpenMailboxSessionFlags flags, CultureInfo cultureInfo, String clientInfoString) Microsoft.Exchange.Data.Storage.MailboxSession.Open(ExchangePrincipal mailboxOwner, WindowsPrincipal authenticatedUser, CultureInfo cultureInfo, String clientInfoString) Microsoft.Exchange.Clients.Owa.Core.OwaWindowsIdentity.CreateMailboxSession(ExchangePrincipal exchangePrincipal, CultureInfo cultureInfo) Microsoft.Exchange.Clients.Owa.Core.UserContext.Load(OwaContext owaContext) Microsoft.Exchange.Clients.Owa.Core.RequestDispatcher.CreateUserContext(OwaContext owaContext, UserContextKey userContextKey, UserContext& userContext) Microsoft.Exchange.Clients.Owa.Core.RequestDispatcher.PrepareRequestWithoutSession(OwaContext owaContext, UserContextCookie userContextCookie) Microsoft.Exchange.Clients.Owa.Core.RequestDispatcher.InternalDispatchRequest(OwaContext owaContext) Microsoft.Exchange.Clients.Owa.Core.RequestDispatcher.DispatchRequest(OwaContext owaContext) System.Web.HttpApplication.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) Inner Exception Exception type: Microsoft.Mapi.MapiExceptionLogonFailed Exception message: MapiExceptionLogonFailed: Unable to open message store. (hr=0x80040111, ec=1010) Diagnostic context: Lid: 18969 EcDoRpcExt2 called [length=781] Lid: 27161 EcDoRpcExt2 returned [ec=0x0][length=124][latency=0] Lid: 23226 --- ROP Parse Start --- Lid: 27962 ROP: ropLogon [254] Lid: 17082 ROP Error: 0x3F2 Lid: 26937 Lid: 21921 StoreEc: 0x3F2 Lid: 27962 ROP: ropExtendedError [250] Lid: 1494 ---- Remote Context Beg ---- Lid: 26426 ROP: ropLogon [254] Lid: 4740 StoreEc: 0x80070005 Lid: 30409 StoreEc: 0x80070005 Lid: 19145 StoreEc: 0x3F2 Lid: 23241 StoreEc: 0x3F2 Lid: 32186 Lid: 8620 StoreEc: 0x3F2 Lid: 1750 ---- Remote Context End ---- Lid: 26849 Lid: 21817 ROP Failure: 0x3F2 Lid: 26297 Lid: 16585 StoreEc: 0x3F2 Lid: 32441 Lid: 1706 StoreEc: 0x3F2 Lid: 24761 Lid: 20665 StoreEc: 0x3F2 Lid: 25785 Lid: 29881 StoreEc: 0x3F2 Call stack Microsoft.Mapi.MapiExceptionHelper.ThrowIfError(String message, Int32 hresult, Int32 ec, DiagnosticContext diagCtx) Microsoft.Mapi.ExRpcConnection.OpenMsgStore(OpenStoreFlag storeFlags, String mailboxDn, Guid mailboxGuid, Guid mdbGuid, MapiStore msgStorePrivate, String& correctServerDn, ClientIdentityInfo clientIdentityAs, String userDnAs, String applicationId, CultureInfo cultureInfo) Microsoft.Mapi.ConnectionCache.OpenMapiStore(String mailboxDn, Guid mailboxGuid, Guid mdbGuid, ClientIdentityInfo clientIdentity, String userDnAs, OpenStoreFlag openStoreFlags, CultureInfo cultureInfo, String applicationId) Microsoft.Mapi.ConnectionCache.OpenMailbox(String mailboxDn, Guid mailboxGuid, Guid mdbGuid, WindowsIdentity windowsIdentityAs, String userDnAs, OpenStoreFlag openStoreFlags, CultureInfo cultureInfo, String applicationId) Microsoft.Exchange.Data.Storage.ConnectionCachePool.OpenMailbox(String serverDn, String userDn, String mailboxDn, Guid mailboxGuid, Guid mdbGuid, Object identity, ConnectFlag connectFlag, OpenStoreFlag openStoreFlag, CultureInfo cultureInfo, String clientInfoString, Boolean secondTry)

Hi, It may be related to Information store/System attendent. Information Store may be starting before the System Attendant and it could not read from my Global Catalog server. I changed the following in the registry: You may refer this link also: http://support.microsoft.com/kb/940845 As mentioned there, Add MSExchangeSA to DependOnService at HKLM\System\CurrentControlSet\Services\MSExchangeIS.Regards from www.windowsadmin.info

Only administrator's mailbox was affected. Other users can get in and out of OWA without any problems. if there was a problem with Sys Attendant, all users would have been affected!

But as you said, it is as the result of a recent permission change.Regards from www.windowsadmin.info

Added MSExchangeSA to DependOnService at HKLM\System\CurrentControlSet\Services\MSExchangeIS Restarted ALL exchange services. Ths problem didn't get resolved.

any more ideas?

hello net_tech, Is outlook in cache mode?? and please check in mailbox properties that he has access to OWA is enable.

Mail-enabling a domain admin account is not recommended. Why the need to do this? The AdminSDHolder object will remove inherited permissions hourly. Lack of inheritance prevents OWA / Active Sync access and other problems. http://support.microsoft.com/kb/907434/en-us