Hybrid Exchange 2007/2013 and Lync EWS Integration

I came across an interesting issue recently with a client currently running Exchange 2007 and looking to migrate to Exchange Online. Since Update Rollup 10 for Exchange 2007 Service Pack 3, it has become possible to coexist Exchange 2oo7 and Exchange 2013.

After installing Exchange 2013 as the Hybrid server, this particular client ran into an issue with the Lync 2013 client losing EWS integration with any mailboxes that still reside on Exchange 2007. The net effect of this is that any users that hadn’t been migrated from Exchange 2007 to Exchange 2013 or Office 365 would have to rely on Outlook MAPI (and Outlook being open) for anything to do with the Personal Information Manager feature of Lync.

Microsoft have confirmed this is a known issue and there is no workaround or hotfix. It’s worth noting that the issue is isolated to a 2013 Hybrid configuration in coexistence with Exchange 2007 only, so a Hybrid Exchange 2010/2007 environment might be the more appropriate solution here.
Update: Microsoft have released a KB article stating that the workaround is to migrate the Exchange 2007 mailboxes to Exchange 2013 http://support.microsoft.com/kb/2941221

Symptoms:

The Lync client will try to connect to Exchange but will prompt with the following:

Legacy versions of Exchange are unable to proxy requests to Exchange 2013, however Exchange 2013 can proxy to legacy versions. This means that a key step of a Hybrid implementation is pointing the Autodiscover service to Exchange 2013, which is when this issue manifested.

In the image below you can clearly see there is an error with the conversation icon and the alert in the bottom right corner is an EWS integration error. The Calendar icon is also missing from the top row.

In Lync “Configuration Information” you’ll notice that there is no server listed for the “Contact List Provider” and under “EWS Information” it shows the status as “EWS not deployed”

Delving into this a little further, looking at the IIS logs on the Exchange 2013 Hybrid server (or the Exchange 2013 server hosting the CAS role), you can see that there is a successful 200 response to the initial authentication request:

2014-03-26 00:36:48 192.168.30.5 POST /autodiscover/autodiscover.svc &CorrelationID=<empty>;&cafeReqId=680dcd6d-2d78-452c-acc2-7659fdc97343; 443 CONTOSO\test1 192.168.10.100 OC/15.0.4569.1503+(Microsoft+Lync) – 200 0 0 15

However when you get to the Autodiscover logs, you can see that the Autodiscover XML file is never actually downloaded by the Lync client due to the mailbox being on Exchange 2007.

2014-03-26T00:36:48.196Z,680dcd6d-2d78-452c-acc2-7659fdc97343,15,0,847,30,,Negotiate,True,test@contoso.com,,OC/15.0.4569.1503 (Microsoft Lync),192.168.10.100,EXCHANGE13,EXCHANGE13.CONTOSO.LOCAL,GetUserSettings,200,InvalidRequest,0,0,1,,,,,GlobalThrottlingPolicy_d74d65fa-cdb4-4e06-be99-6f259ea1158a,,,0,8,0,8,,0,15.63,ADSessionSettingsFromAddress=0;ADRecipientSessionFindBySid=15.63;RequestedUser=test@contoso.com;S:ServiceCommonMetadata.RequestSize=1527;S:WLM.Bal=300000;S:WLM.BT=Ews;S:BudgetMetadata.MaxConn=27;S:BudgetMetadata.MaxBurst=300000;S:BudgetMetadata.BeginBalance=300000;S:BudgetMetadata.Cutoff=3000000;S:BudgetMetadata.RechargeRate=900000;S:BudgetMetadata.IsServiceAct=False;S:BudgetMetadata.LiveTime=00:01:00.2078770;S:BudgetMetadata.EndBalance=300000;Dbl:WLM.TS=15.63;I32:ATE.C[DC01.CONTOSO.LOCAL]=1;F:ATE.AL[DC01.CONTOSO.LOCAL]=0;I32:ADS.C[DC01]=1;F:ADS.AL[DC01]=4.9612,,ErrorMessage=The SOAP-based AutoDiscover service is not available for mailboxes on Exchange 2007.;