I encountered a problem with our BES Express server recently that has us stumped.
When attempting to add a device/user to the BES some AD / Exchange accounts are not available on the BES
We implemented a new Exchange server a few months ago, upgrading from 2007 to 2010 but I am not 100% the issue started around this time.
We have a mix of Active Directory domain controllers (Server 2008 and 2003).
BES Express 5.0.3, MS Exchange 2010, Active Directory 2003 Functional