Same time Most of the Outlook2k10 users Disconnect and Event 9646 32 MAPI Session event is logged

Question

Exchange 2010 SP3 RU5, windows 2008 R2 SP1 and outlook 2010.
4 CAS Servers behind F5 Load balancer and 7 Mailbox servers are configured in DAG.
issue: 
- For most of the users Outlook shows 'Disconnected' state and outlook will not connect even if you restart the client PC.
- All effected users are from different databases and are on different mailbox servers.
- For all the effected users, we are receiving 9646 Event for exceeding 32 MAPI Sessions. And this event is coming on all mailbox servers at same time, So I am thinking it is some common problem, but couldn't figured it out.
-- To fix the issue i have restarted the Exchange servers..
- In RPC Logs, I can see Session drop errors.
============
OUTLOOK.EXE ncacn_ip_tcp 0x6BA (rpc::Exception) 57:16.0 SessionDropped RpcEndPoint: [ServerUnavailableException] Connection must be re-established -> [SessionDeadException] Connection is severed (ConnectionFailedTransientException).
Client needs to reconnect. -> [ConnectionFailedTransientException] Cannot get synchronize buffers from Microsoft.Exchange.Data.Storage.SynchronizerProviderBase. -> [MapiExceptionNetworkError] MapiExceptionNetworkError: Synchronization failure. (hr=0x80040115,
ec=0)   
 OUTLOOK.EXE ncacn_http 0x6BA (rpc::Exception) 36:08.7 SessionDropped RpcEndPoint: [ServerUnavailableException] Connection must be re-established -> [SessionDeadException] Connection is severed (ConnectionFailedTransientException).
Client needs to reconnect. -> [ConnectionFailedTransientException] Cannot get recipient table. -> [MapiExceptionNetworkError] MapiExceptionNetworkError: Unable to get recipient table. (hr=0x80040115, ec=0)   
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- I found KB http://support.microsoft.com/kb/2781488  for similar issue, but as per the article issue is fixed in SP3 RU1 - But we are running SP3 RU5
Any help regarding this issue will be highly appreciated.
Looking forward to the response,
Regards,
Ghouse

Answer 1

Hi Ghouse,
Please check whether there is a service account for a third-party application that interacts with Exchange server.
Generally, event 4969 occurs because the default maximum number(by default the value is 32) of connections that an account can open was exceeded. There should be a mapi session in your Event description. Please run the following cmdlet to grant the service
account the "View Information Store status" permission:
Add-ADPermission -Identity “Exchange Administrative Group (FYDIBOHF23SPDLT)” -User account_or_group_name
-AccessRights ExtendedRight -ExtendedRights "View information store status" -InhertanceType Descendents
For more information about it, please refer to the following KB:
http://support.microsoft.com/kb/2742012
If it doesn’t work, please check whether the problematic users can access OWA or work well in OWA. Also collect the Test E-mail AutoConfiguration results in Outlook for further anylysis.
Thanks,
Winnie Liang
TechNet Community Support