Doing an a migration today from Exchange 2003 to 2010 and once I’ve installed the Exchange 2010 server, I rebooted and logged back on to it.
I got the following error “No Exchange servers are available in any active directory sites.”
After a little investigation, I realised that I was logging on with the local administrator account rather than the domain administrator account. Doh!!!
Log off and back on using the RIGHT domain account and it works fine now!