MailboxInSiteFailoverException - OWA session error on database *over (Exchange 2013 SP1)

Question

Hi all, I have noticed an issue with OWA when database(s) are failed over between DAG members.  The environments in question (issue can be reproduced in separate implementations of 2013 SP1 all-role servers) are 2 or more DAG members within the same
AD site/subnet.  These are also fresh implementations with SP1 and not upgraded.  Exchange servers are load balanced via Netscaler. 
So to the issue - OWA users experience the below "..MailboxInSiteFailoverException" message when the database copy is activated.  Exchange does not immediately proxy the requests to the active database.  You can wait several minutes and
the issue is resolved by refreshing the browser or if you recycle the MSExchangeOWAAppPool on both DAG members, the issue is resolved immediately (OWA session re-established on refresh).
Testing so far involved opening multiple OWA sessions and activating a database copy.  At that point, upon refresh of the browser the below error is shown (in all test browsers/sessions below) where I would expect any DAG member to be able to proxy
the client request to the active database server immediately (and not after several minutes).
https://netscaler_LB/owa
https://ex2013server-1/owa
https://ex2013server-2/owa

Answer 1

Hi Simon, I have tested with no firewall on the exchange servers and on client machines within the same subnet as the servers.  All with the same results.
I can see many ASP.NET 4.0.30319.0 Event ID 1309 logs similar to this and other threads (http://social.technet.microsoft.com/Forums/windowsserver/en-US/c938dda0-b3bc-4544-851e-f27b503cf4ed/exchange-2013-event-id-1309-source-aspnet-40303190).
IIS logs show similar monitoring mailbox issues but I am still currently looking through the logs.  Thanks for your input.
2014-03-30 00:00:23 127.0.0.1 POST /owa/proxylogon.owa - 444 - 127.0.0.1 Mozilla/4.0+(compatible;+MSIE+9.0;+Windows+NT+6.1;+MSEXCHMON;+ACTIVEMONITORING;+OWADEEPTEST) - 401 0 0 13
2014-03-30 00:00:23 127.0.0.1 POST /owa/proxylogon.owa - 444 - 127.0.0.1 Mozilla/4.0+(compatible;+MSIE+9.0;+Windows+NT+6.1;+MSEXCHMON;+ACTIVEMONITORING;+OWADEEPTEST) - 401 0 0 13
2014-03-30 00:00:23 127.0.0.1 POST /owa/proxylogon.owa - 444 - 127.0.0.1 Mozilla/4.0+(compatible;+MSIE+9.0;+Windows+NT+6.1;+MSEXCHMON;+ACTIVEMONITORING;+OWADEEPTEST) - 401 1 2148074254 0
2014-03-30 00:00:23 127.0.0.1 POST /owa/proxylogon.owa - 444 - 127.0.0.1 Mozilla/4.0+(compatible;+MSIE+9.0;+Windows+NT+6.1;+MSEXCHMON;+ACTIVEMONITORING;+OWADEEPTEST) - 401 1 2148074254 0
2014-03-30 00:01:23 ::1 POST /owa/proxylogon.owa &ex=UE:Microsoft.Exchange.Data.Storage.IllegalCrossServerConnectionException 444 DOMAIN\SM_3ce57cd622aa4655a ::1 Mozilla/4.0+(compatible;+MSIE+9.0;+Windows+NT+6.1;+MSEXCHMON;+ACTIVEMONITORING;+OWADEEPTEST)
- 302 0 0 47
2014-03-30 00:01:23 ::1 POST /owa/proxylogon.owa &ex=UE:Microsoft.Exchange.Data.Storage.IllegalCrossServerConnectionException 444 DOMAIN\SM_2891f9d41af2422e8 ::1 Mozilla/4.0+(compatible;+MSIE+9.0;+Windows+NT+6.1;+MSEXCHMON;+ACTIVEMONITORING;+OWADEEPTEST)
- 302 0 0 47