I have installed exchange 2010 and also have exchange 2007 in the same AD site.
Everything works internally but when trying to access EWA externally I get the result:The Client Access Server version does not match the accessed resource's Mailbox Server version. This is when I am
trying to get to a mailbox that I have moved to Exchange 2010. If I try to access a 2007 mailbox it works fine.
This tells me that the request for the 2010 mailbox is being redirected to the CAS2007 even though it should be using CAS2010.
Another clue is that when I access OWA over the web, it gives me the 2007 login form instead of the exchange 2010 form. Also once again I am unable to log in with mailboxes on the 2010 server but can log in with 2007 mailboxes.
Does anyone know what could be going on here?