Can someone help me? What do I need to do to gain mailbox access across a domain/site through an ISA VPN for a newly upgraded Exchange 2000 system? It was just upgraded from EX5.5 which still exists on the site...I had access previously. I HAVE already removed the "deny access" to my Domain admin group, (which got me access in my original domain), but something is still blocking me from access to the new EX2000 server... I am getting "information store cannot be opened" message... Thanks!