Microsoft.Exchange.Data.Storage.ConnectionFailedTransientException

How to clear Exchange transaction log

Hellow Experts,

I don't know much about exchange server 2007.
Currently our user have problem accessessing emails throw owa. they get error


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 "Outlook web access could not connect to Microsoft Exchange.

Request
Url: https://webmail.site.org:443/owa/default.aspx
User host address: 10.2.2.22

Exception
Exception type: Microsoft.Exchange.Data.Storage.ConnectionFailedTransientException
Exception message: Cannot open mailbox /o=SITEorg/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=user1.user1.

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.MapiExceptionNetworkError
Exception message: MapiExceptionNetworkError: Unable to make connection to the server. (hr=0x80040115, ec=-2147221227) Diagnostic context: ...... Lid: 12696 dwParam: 0x6D9 Msg: EEInfo: Generation Time: 2011-07-11 06:48:12:563 Lid: 10648 dwParam: 0x6D9 Msg: EEInfo: Generating component: 2 Lid: 14744 dwParam: 0x6D9 Msg: EEInfo: Status: 1753 Lid: 9624 dwParam: 0x6D9 Msg: EEInfo: Detection location: 501 Lid: 13720 dwParam: 0x6D9 Msg: EEInfo: Flags: 0 Lid: 11672 dwParam: 0x6D9 Msg: EEInfo: NumberOfParameters: 4 Lid: 8856 dwParam: 0x6D9 Msg: EEInfo: prm[0]: Unicode string: ncacn_ip_tcp Lid: 8856 dwParam: 0x6D9 Msg: EEInfo: prm[1]: Unicode string: Exch01.SITEuser1.local Lid: 12952 dwParam: 0x6D9 Msg: EEInfo: prm[2]: Long val: -1527653632 Lid: 12952 dwParam: 0x6D9 Msg: EEInfo: prm[3]: Long val: 382312662 Lid: 19778 Lid: 27970 StoreEc: 0x80040115 Lid: 17730 Lid: 25922 StoreEc: 0x80040115

Call stack
Microsoft.Mapi.MapiExceptionHelper.ThrowIfError(String message, Int32 hresult, Int32 ec, DiagnosticContext diagCtx)
Microsoft.Mapi.ExRpcConnection.Create(ConnectionCache connectionCache, ExRpcConnectionCreateFlag createFlags, ConnectFlag connectFlags, String serverDn, String userDn, String user, String domain, String password, String httpProxyServerName, Int32 ulConMod, Int32 lcidString, Int32 lcidSort, Int32 cpid, Int32 cReconnectIntervalInMins, Int32 cbRpcBufferSize, Int32 cbAuxBufferSize)
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)


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I checked "Exchange Transaction Logs Drive it is full,
How to clear the logs under this drive?
what else i need to do to make sure exchange come back to live.

can you please explain this to me step-by-step as I don't know much about exchange

thanks