We run Exchange 2007. We are a school the has about 1500 AD account and mail boxes. The issue that has come up and in all our wisdom the only fix we have is to delete the mailbox and AD account then re-create it (deleting only the mailbox didn't work). All the preferences are exactly the same as everyone else. It just wont log on. The error message is as follows (I have just copied and pasted so sorry about the format): Outlook Web Access could not connect to Microsoft Exchange. If the problem continues, contact technical support for your organization. Copy error details to clipboard Show details Request Url: https://xxx.xxx.vic.edu.au:443/owa/default.aspx User host address: xx.xxx.xx.xx Exception Exception type: Microsoft.Exchange.Data.Storage.ConnectionFailedTransientException Exception message: Cannot open mailbox /o=Dromana/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=COL0035. 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=-2147221231) Diagnostic context: Lid: 18969 EcDoRpcExt2 called [length=599] Lid: 27161 EcDoRpcExt2 returned [ec=0x0][length=132][latency=15] Lid: 23226 --- ROP Parse Start --- Lid: 27962 ROP: ropLogon [254] Lid: 17082 ROP Error: 0x80040111 Lid: 26937 Lid: 21921 StoreEc: 0x80040111 Lid: 27962 ROP: ropExtendedError [250] Lid: 1494 ---- Remote Context Beg ---- Lid: 26426 ROP: ropLogon [254] Lid: 22787 Error: 0x0 Lid: 13032 StoreEc: 0x8004010F Lid: 59409 Lid: 45073 Lid: 11173 StoreEc: 0x80040111 Lid: 22970 Lid: 8620 StoreEc: 0x80040111 Lid: 1750 ---- Remote Context End ---- Lid: 26849 Lid: 21817 ROP Failure: 0x80040111 Lid: 26297 Lid: 16585 StoreEc: 0x80040111 Lid: 32441 Lid: 1706 StoreEc: 0x80040111 Lid: 24761 Lid: 20665 StoreEc: 0x80040111 Lid: 25785 Lid: 29881 StoreEc: 0x80040111 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) Any ideas? Cheers

If this is happening occasionally to random mailboxes, then I suspect some corruption in the database or messages. Are there any event log entries occurring concurrently when trying to open the mailbox?Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

Because the new users can log in OWA. So I think Exchange works fine. According to the error message, I doubt you have ever did a migration. >>message: Cannot open mailbox /o=Dromana/ou=Exchange >>Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=COL0035.” Could you please try to create a new mailbox database, and move a mailbox to the new mailbox database? Does the moved user can log in OWA ? 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.

Can the user log into Outlook? When this happens verify that the DN that the error shows exists for the particular user either in his legacyexchangedn field using adsiedit or ldp. Cannot open mailbox /o=Dromana/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=COL0035. James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com