We have one OCS Server in use for 200 users. Our Top Level domain within the organization is CORP.LOCAL. So all internal servers resolve to SERVERXXX.CORP.LOCAL... including the OCS server... OCSSVR.CORP.LOCAL.
But was also have two separate internal email routing domains... company1.com and company2.com. But both route through Exchange 2007, and all in their respective AD OUs... CORP.LOCAL\USERS\COMPANY1 and CORP.LOCAL\USERS\COMPANY2. All users within Company1 are working properly, but cannot get user within Company2 to connect. "Cannot sign in because the server is temporarily unavailable."
And if I move a user from one OU (CORP.LOCAL\USERS\COMPANY2) to the other (COMPANY1), and update their email and sip domain's... it works fine.
Do I need to specify the two domains indepentantly within OCS? I have both domains listed in Forest - corp.local, Status, General Settings, Supported Domains list: corp.local, company1.com, company2.com. And the Default Routing Domain is "corp.local".
We don't use any Edge Servers, so there is no external access to any of this... all internal.