I am getting below warning messages in application log in exchange 2013 CAS Servers and my outlook clients are getting disconnected randomly.My Exchange Servers are running on Windows 2012 and domain controller is running on windows 2008 R2.

I have two CAS servers with NLB configuration and 2 Mailbox servers with DAG configuration.

Please help...

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Event code: 3005

Event message: An unhandled exception has occurred.

Event time: 7/25/2013 7:28:06 PM

Event time (UTC): 7/25/2013 1:58:06 PM

Event ID: 6ff66232e21d4f92b0c6702501751a59

Event sequence: 2

Event occurrence: 1

Event detail code: 0

Application information:

    Application domain: /LM/W3SVC/1/ROOT/Rpc-2-130192339023474616

    Trust level: Full

    Application Virtual Path: /Rpc

    Application Path: C:\Program Files\Microsoft\Exchange Server\V15\FrontEnd\HttpProxy\rpc\

    Machine name: EXCH-CAS-01

Process information:

    Process ID: 2848

    Process name: w3wp.exe

    Account name: NT AUTHORITY\SYSTEM

Exception information:

    Exception type: HttpException

    Exception message: The client disconnected.

   at Microsoft.Exchange.HttpProxy.ProxyRequestHandler.EndProcessRequest(IAsyncResult result)

   at System.Web.HttpApplication.CallHandlerExecutionStep.OnAsyncHandlerCompletion(IAsyncResult ar)

Request information:

    Request URL: https://email.domain.com:443/rpc/rpcproxy.dll?e270821d-7398-4607-aa2f-cb9816754bc2@domain.com:6001

    Request path: /rpc/rpcproxy.dll

    User host address: 14.140.240.220

    User: EXCH\Pankaj.k

    Is authenticated: True

    Authentication Type: Negotiate

    Thread account name: NT AUTHORITY\SYSTEM

Thread information:

    Thread ID: 18

    Thread account name: NT AUTHORITY\SYSTEM

    Is impersonating: False

    Stack trace:    at Microsoft.Exchange.HttpProxy.ProxyRequestHandler.EndProcessRequest(IAsyncResult result)

   at System.Web.HttpApplication.CallHandlerExecutionStep.OnAsyncHandlerCompletion(IAsyncResult ar)

Custom event details:

Hello,

I recommend yo uadding a registry key that extends the timeout with the following key:

HKEY_LOCAL_MACHINE/Software/Policies/Microsoft/Windows NT/MinimumConnectionTimeout

and a DWORD Value of 120 to check the result.

If the issue persists, I recommend you check if there is any error in application log.