Users are getting a "Server unavailable" message when users are trying to set Out Of Office and accessing Shared Calendar's. I have gone through our exchange environment and could not find the issue. I opened a ticket with Microsoft and they could not find any issues either. I also worked with our load balancer support and they went through everything and could not find any issues. Users are able to access everything via OWA, but with Outlook 2010 and 2013 they are getting this message.
We are running on a 2 server CAS Array and a 2 server DAG, running on Exchange 2010 SP3 rollup 1. The load balancer we are using is from Kemp Technologies.