HTTP 500 error when opening a legacy shared mailbox in OWA 2013 (Exchange 2007/2013 coexistence environment)

Question

Hi,
Our Exchange 2013/2007 coexistence environment is set up and all is working apart from this:
Mailbox A has full permissions to Mailbox B. Mailbox A is migrated to Exchange 2013, but Mailbox B remains on Exchange 2007. If I login to Outlook Web App 2013 as Mailbox A and then "Open another mailbox..." and select Mailbox B, a new window opens
up saying "HTTP 500 Internal Server Error". The URL it is trying is :
https://webmail.ourdomain.com/owa/[email protected]/?offline=disabled
( I can open Mailbox A in Outlook 2010 and do "Open Other users's folder.." and Mailbox B opens up just fine. )
Our legacy CAS server's External and Internal URLs are set to :
https://legacy.ourdomain.com/owa
and the Exchange 2013 CAS server's External and Internal URLs are set to :
https://webmail.ourdomain.com/owa
We have FBA enabled on both the E2K7 and E2K13 OWA
In the IIS logs:
2015-03-02 16:36:50 <E2K13_IP> POST /owa/service.svc action=SubscribeToNotification&UA=0&ID=-25&AC=1&CorrelationID=c2899211-568d-4da4-a163-351a8621c9fd_142531419466924;&cafeReqId=7ffae082-a96f-42fd-85f8-bf23775ed5de; 443 ourdomain.com\MailboxA
<LoadBalancer_IP> Mozilla/4.0+(compatible;+MSIE+8.0;+Windows+NT+6.1;+WOW64;+Trident/4.0;+SLCC2;+.NET+CLR+2.0.50727;+.NET+CLR+3.5.30729;+.NET+CLR+3.0.30729;+Media+Center+PC+6.0)
https://webmail.ourdomain.com/owa/#path=/mail 200 0 0 109
2015-03-02 16:36:50 <E2K13_IP> GET /owa/ offline=disabled&CorrelationID=<empty>;&cafeReqId=7c8e137f-cdb7-4449-9cb8-f36f94539244; 443 ourdomain.com\MailboxA <LoadBalancer_IP> Mozilla/4.0+(compatible;+MSIE+8.0;+Windows+NT+6.1;+WOW64;+Trident/4.0;+SLCC2;+.NET+CLR+2.0.50727;+.NET+CLR+3.5.30729;+.NET+CLR+3.0.30729;+Media+Center+PC+6.0)
- 500 0 0 265
In the OWA HTTP Proxy logs:
2015-03-02T16:36:50.096Z,7c8e137f-cdb7-4449-9cb8-f36f94539244,15,0,913,7,,Owa,webmail.ourdomain.com,/owa/,,FBA,True,ourdomain.com\MailboxA,ourdomain.com,[email protected],Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2;
.NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0),<LoadBalancer_IP>,<Exchange2013ServerName>,500,,ServerNotFound,GET,,,,,ExplicitLogon-SMTP-Header,,,,0,,,,40,9,,0,7;,7,,0,7,,0,46.8643,0,,,,,,,,,1,10,0,,10,,50,50,?offline=disabled,,BeginRequest=2015-03-02T16:36:50.049Z;CorrelationID=<empty>;ProxyState-Run=None;ServerLocatorRefresh=beebf732-0f99-47a0-9f36-d266573f1510;RefreshingCacheEntry=CacheEntry(BackEndServer
<Exchange2007ServerName>.ourdomain.com~1912832083|ResourceForest |LastRefreshTime 2015-03-02T16:01:29.3265514Z|IsSourceCachedData False);ProxyState-Complete=CalculateBackEnd;EndRequest=2015-03-02T16:36:50.096Z;I32:ADS.C[<DC_Name>]=1;F:ADS.AL[<DC_Name>]=6.6401;I32:ATE.C[<DC_Name>.ourdomain.com]=1;F:ATE.AL[<DC_Name>.ourdomain.com]=0,HttpProxyException=Microsoft.Exchange.HttpProxy.HttpProxyException:
The server <Exchange2013ServerName>.ourdomain.com was not found in the topology. ---> Microsoft.Exchange.Data.Storage.ServerNotFoundException: The server <Exchange2013ServerName>.ourdomain.com was not found in the topology.   
at Microsoft.Exchange.Data.Storage.ServiceTopology.GetSite(String serverFullyQualifiedDomainName)    at Microsoft.Exchange.Data.ApplicationLogic.Cafe.HttpProxyBackEndHelper.GetServiceTopologyWithSites(String serverFqdn  ServiceTopology
topology)    at Microsoft.Exchange.Data.ApplicationLogic.Cafe.HttpProxyBackEndHelper.GetE12ExternalUrl[ServiceType](BackEndServer mailboxServer)    at Microsoft.Exchange.HttpProxy.OwaProxyRequestHandler.GetE12TargetServer(BackEndServer
mailboxServer)    at Microsoft.Exchange.HttpProxy.BEServerCookieProxyRequestHandler`1.GetDownLevelClientAccessServer(AnchorMailbox anchorMailbox  BackEndServer mailboxServer)    at Microsoft.Exchange.HttpProxy.LatencyTracker.GetLatency[T](Func`1
operationToTrack  Int64& latency)    at Microsoft.Exchange.HttpProxy.ProxyRequestHandler.InternalOnCalculateTargetBackEndCompleted(TargetCalculationCallbackBeacon beacon)    at Microsoft.Exchange.HttpProxy.ProxyRequestHandler.<>c__DisplayClass3b.<OnCalculateTargetBackEndCompleted>b__3a()   
--- End of inner exception stack trace ---;
Hoping that somebody can help ?
Thanks

Answer 1

Hi Ansev,
Thank you for your question.
By my testing, user who was migrated to Exchange 2013 cannot access mailbox on Exchange 2007 with 500 error, although user account have “Full Access Permission” to mailbox on Exchange 2007.
I suggest we migrate account which has “Full Access Permission” for other user  to Exchange 2013.
If there are any questions regarding this issue, please be free to let me know. 
Best Regard,
Jim
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Jim Xu
TechNet Community Support