I'm having some connectivity problems in an exchange 2010 lab that was built from copies of production DC's and Exchange components. The production environment is running Exchange 2003 but as of yet has no exchange 2010 presence. In the lab we extended the schema for 2010, installed one 2010 server running the cas/ht role, and a second server running the mailbox role. I'm having connectivity problems between the CAS server and the Mailbox Server and I've found that it ultimately comes down to some type of permission or access error related to the error below. MapiExceptionNetworkError: Unable to make admin interface connection to server. (hr=0x80040115, ec=-2147221227) I've created a new mailbox on the 2010 mailbox server and cannot access it via OWA or Outlook because of the error above. I also cannot migrate a mailbox from the lab exchange 2003 server because of this same error. The lab is a single flat subnet, so there are no routers or firewalls between these two servers or any other lab components. I've also disabled the Windows 2008 Firewall on each 2010 server, so there should be no blocking there. I also added the Exchange Trusted Servers domain group to the local administrators group on each server, and the account I'm using for all operations is an Exchange Full Administrator with domain, schema, and enterprise admin rights in the forest. The .net tcp port sharing service is also started on both servers. I'm not sure where else to turn. It's a pretty straightforward configuration and we don't want to proceed in production until we can figure out why these errors are occuring in the lab with such a basic configuration. Any help would be greatly appreciated.

Solved my own issue. Turns out there were some static host references in DNS that were blocking dynamic DNS updates and pointing to invalid IP addresses. (Duh!) Cleaned these out and allowed the new records to dynamically populate, and everything was fine. Forgot my own troubleshooting rule - go for the easy solutions first!