Exchange 2007 Mailbox Access

Hello,

I have 3 Exchange 2003 servers and one exchange 2007. I granted domain
admins access to all mailboxes and it works fine except when the mailbox of
the domain admin resides on the third exchange 2003 server. For some reason
when the mailbox resides on this third server, they cannot open mailboxes
that are located on the exchange 2007 server. They can still open up
mailboxes on the 2003 exchange servers but not the 2007 mailboxes. If I move
their(domain admin) mailbox to another 2003 or 2007 server, it works again.

Any ideas? i looked through all the permissions that apply to the server but
I can not find anything obvious. I also noticed when on the third problem
exchange 2003 server, the Domain admin can open the same box via OWA with no
problems, it's just that they can't open it via MAPI.



Thanks in advance,