We have Exchange 2010 and Exchange 2013 co-existence scenario and Federated with one domain xyz.com
From Exchange 2010 works fine both direction to xyz.com (which is on exchange 2010 SP3 ) and from xyz domain works free/busy Exchange 2010 and Exchange 2013 free /busy.
But From exchange 2013 to xyz.com domain is Free/busy not working the in OWA 2013.
Getting below error message
Free/busy information couldn’t be retrieved because the attendee's Mailbox server is busy and MS says on this error
http://support.microsoft.com/kb/2838688/en-us
TargersharingEPR should be null but in our case Free/busy running only on the targetsharingepr end point
TargetSharingEpr : https://mail.xyz.com/EWS/Exchange.asmx
TargetOwaURL :
TargetAutodiscoverEpr :
Any thoughts on this issue ?
ksrugi