Active sync issue when published via MS Web Application Proxy

Exchange 2013 CU7

If you are getting this error on the CAS servers

[Eas] The number of outstanding requests for guard TargetBackend(“servername”) has exceeded the max limit 150. Current request will be rejected.

And this error on the Microsoft Web Application Proxy

The HTTP response from the back end server was not received within the expected interval. Expected interval: 300 seconds.

Try

Reference here 

  • On all CAS servers:

    In \Exchange Server\V15\FrontEnd\HttpProxy\sync\web.config, add this key in the <appSettings> node.

    <add key=”HttpProxy.ConcurrencyGuards.TargetBackendLimit” value=”5000″ />

    In \Exchange Server\V15\FrontEnd\HttpProxy\rpc\web.config, add this key in the <appSettings> node.

    <add key=”HttpProxy.ConcurrencyGuards.TargetBackendLimit” value=”5000″ />

    After this change recycle the MSExchangeSyncAppPool and MSExchangeRPCProxyAppPool in IIS manager.

    After this, we stopped getting Event ID 2002, and all Connection_Dropped_Event_List_Full stopped appearing in Httperror logs.

     

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5 thoughts on “Active sync issue when published via MS Web Application Proxy

    1. eddwatton Post author

      Sorry, I don’t know where the files are for 2010 but if I find out I will update this post. I’m assuming in not in the same location but the V14 directory?

      Edd

      Reply
  1. Thomas Guldberg

    Hi Edd
    We installed CU11 for Exchange 2013 yesterday (we are Migrating from Exchange 2007 and have mapi/http issues that are resolved in CU11).
    We ran CU9 untill the upgrade and did the changes to the web.config files as you described to get rid of the “[Eas] The number of outstanding requests for guard TargetBackend(“servername”) has exceeded the max limit 150. Current request will be rejected.”

    After we installed CU11 (and the web.config files of course were updated) we applied the changes again. This caused the NetScaler cluster to mark Active Sync and rpc as down on all our eight servers and no one could synchronize their mobile devices with Active Sync.
    As soon as we removed the “” line from the web.config files everything started working again.

    We are currently working with MS to resolve this issue as the “old” warning is back due to the fact that we cannot apply the changes to the web.config files.

    Hope this helps if you are going to apply CU11

    Reply
  2. Wayde

    We currently have Exchange 2013 CU10 and recently completed the migration from Exchange 2007. We are also this event (2002) on one of our Exchange CAS servers. But, after making the changes referenced above and bouncing the app pools, users were not able to connect to Exchange. Deleting the lines from the web.config files and bouncing the app pools again got users connected again but the 2002 events returned.

    Reply

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