I'm having inconsistent Activesync connections issues between 2 of my servers and I would appreciate any input anyone would care to offer.
We have 3 exchange boxes split between 2 active directory sites.
Server1 and Server2 are in different sites and are both internet facing through ISA servers. Server3 is primarily a mailbox database store that sits in the same AD site as Server1.
All 3 servers have CAS and Mailbox roles installed, are setup on Exch2010 with the latest rollout running on fully patched Win 2008 R2 boxes.
For activesync connections, users can access mailboxes stored on Server3 using either Server1 or Server2 with no issue. Oddly, for mailboxes stored on Server1, users can access their mailbox when connecting through Server1, but not when connecting through Server2.
The issue was observed by a user after we moved his mailbox from Server3 to Server1, and his mobile phone started reporting that it was unable to sync. New account setup attempts on other mobile phones for his account produce a simple error of "Unable to connect to server", but leave no logs on Server2 as a hint.
Anyone have idea what might be getting in the way of Server1 and Server2 communicating effectively?