We have five Exchange servers in our environment. Three are in production and hosting mailboxes. These three are at different locations and each is setup for OWA, OMA, and RPC over HTTPS over their respective internet connections. We use forms based auth and ssl for OWA and my predecessor setup a second virtual directory called exchange-oma that was setup without SSL and modified the registry so AcrtiveSync would point to it.
We used to have 4 servers with this exact config but one of our offices closed. I moved this server and configured it as a front end server. I turned off forms based auth and require ssl on the three existing production servers. I can connect through the Front End server just fine for OWA, and RPC over HTTPS no matter what server the user mailbox is on. However accessing OMA with Activesync does not work. I receive a 85010014 error on the phones and event id 9175 in the log on the Front End server.
The interesting thing is I setup a new server that is just to host mailboxes. I duplicated the exchange-oma directory on it and it works. Any mailbox I put on this server I can access using Activesync, OWA, or rpc over https through the Front End server. I can't figure out why it works on this new server but won't on any of my existing three production ones.