We recieve a lot of 4009 errors on exchange 2013 (CU11 installed):
Process Microsoft.Exchange.InfoWorker.Common.Delayed`1[System.String]: Unable to open connection for mailbox <David Grof>SMTP:username@domain.com. Exception returned is: Microsoft.Exchange.Data.Storage.StorageTransientException: Cannot open mailbox
/o=Company/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Configuration/cn=Servers/cn=EXCHANGE2013/cn=Microsoft System Attendant. ---> Microsoft.Mapi.MapiExceptionRpcServerTooBusy: MapiExceptionRpcServerTooBusy: Unable to make connection to the server.
(hr=0x80004005, ec=2419)
Diagnostic context:
Lid: 41841 StoreEc: 0x973
Lid: 51059
Lid: 62321 StoreEc: 0x973
Lid: 47987
Lid: 50033 StoreEc: 0x973
Lid: 50544 ClientVersion: 15.0.1156.6
Lid: 52080 StoreEc: 0x973
Lid: 51152
Lid: 52465 StoreEc: 0x973
Lid: 60065
Lid: 33777 StoreEc: 0x973
Lid: 59805
Lid: 52487 StoreEc: 0x973
Lid: 19778
Lid: 27970 StoreEc: 0x973
Lid: 17730
Lid: 25922 StoreEc: 0x973
at Microsoft.Mapi.MapiExceptionHelper.InternalThrowIfErrorOrWarning(String message, Int32 hresult, Boolean allowWarnings, Int32 ec, DiagnosticContext diagCtx, Exception innerException)
at Microsoft.Mapi.MapiExceptionHelper.ThrowIfError(String message, Int32 hresult, IExInterface iUnknown, Exception innerException)
at Microsoft.Mapi.ExRpcConnectionFactory.Create(ExRpcConnectionInfo connectionInfo)
at Microsoft.Mapi.MapiStore.OpenMapiStore(String serverDn, String userDn, String mailboxDn, Guid guidMailbox, Guid guidMdb, String userName, String domainName, String password, String httpProxyServerName, ConnectFlag connectFlags, OpenStoreFlag
storeFlags, CultureInfo cultureInfo, Boolean wantRedirect, String& correctServerDN, ClientIdentityInfo clientIdentity, Boolean unifiedLogon, String applicationId, Client xropClient, Boolean wantWebServices, Byte[] clientSessionInfo, TimeSpan connectionTimeout,
TimeSpan callTimeout, Byte[] tenantHint)
at Microsoft.Mapi.MapiStore.OpenMailbox(String serverDn, String userDn, Guid guidMailbox, Guid guidMdb, String userName, String domainName, String password, ConnectFlag connectFlags, OpenStoreFlag storeFlags, CultureInfo cultureInfo, WindowsIdentity
windowsIdentity, String applicationId, Byte[] tenantPartitionHint, Boolean unifiedLogon)
at Microsoft.Exchange.Data.Storage.MailboxSession.ForceOpen(MapiStore linkedStore, Boolean unifiedSession)
--- End of inner exception stack trace ---
at Microsoft.Exchange.Data.Storage.MailboxSession.ForceOpen(MapiStore linkedStore, Boolean unifiedSession)
at Microsoft.Exchange.Data.Storage.MailboxSession.Initialize(MapiStore linkedStore, LogonType logonType, IExchangePrincipal owner, DelegateLogonUser delegateUser, Object identity, OpenMailboxSessionFlags flags, GenericIdentity auxiliaryIdentity,
Boolean unifiedSession)
at Microsoft.Exchange.Data.Storage.MailboxSession.<>c__DisplayClass1c.<CreateMailboxSession>b__1a(MailboxSession mailboxSession)
at Microsoft.Exchange.Data.Storage.MailboxSession.InternalCreateMailboxSession(LogonType logonType, IExchangePrincipal owner, DelegateLogonUser delegatedUser, CultureInfo cultureInfo, String clientInfoString, IBudget budget, Action`1 initializeMailboxSession,
InitializeMailboxSessionFailure initializeMailboxSessionFailure, MailboxSessionSharableDataManager sharedDataManager)
at Microsoft.Exchange.Data.Storage.MailboxSession.CreateMailboxSession(LogonType logonType, IExchangePrincipal owner, DelegateLogonUser delegateUser, Object identity, OpenMailboxSessionFlags flags, CultureInfo cultureInfo, String clientInfoString,
PropertyDefinition[] mailboxProperties, IList`1 foldersToInit, GenericIdentity auxiliaryIdentity, IBudget budget, Boolean unifiedSession, MailboxSessionSharableDataManager sharedDataManager, UnifiedGroupMemberType memberType)
at Microsoft.Exchange.Data.Storage.MailboxSession.ConfigurableOpen(IExchangePrincipal mailbox, MailboxAccessInfo accessInfo, CultureInfo cultureInfo, String clientInfoString, LogonType logonType, PropertyDefinition[] mailboxProperties, InitializationFlags
initFlags, IList`1 foldersToInit, IBudget budget, Boolean unifiedSession, MailboxSessionSharableDataManager sharedDataManager, UnifiedGroupMemberType memberType)
at Microsoft.Exchange.Data.Storage.MailboxSession.OpenAsSystemService(IExchangePrincipal mailboxOwner, CultureInfo cultureInfo, String clientInfoString, Boolean readOnly)
at Microsoft.Exchange.InfoWorker.Common.Availability.CalendarQuery.GetDataInternal(FreeBusyQuery freeBusyQuery, EmailAddress emailAddress).
bostjanc