How-To procedure – Exchange 2010 – all SPs – After CAS array setup : do not forget to update this Database property !
Even if you have your CAS Array already established, double check the RPCClientAccessServer attribute on all your databases ! Experience show that on 80% cases, customers still have the wrong value for some databases…
How-to procedure - Exchange Server 2010 SP1 - Operations - Updating servers from a DAG.pdf