The Exchange Best Practices Analyzer returns the following error when running a health check: The Directory Service Access (DSAccess) process on server SERVER reports that Active Directory server SERVER2.domain.local is not functional. We have a total of three DCs and it returns this error for the other two DCs. It does not return this error for itself. Unfortunately, the person who installed Exchange installed it on a DC. I've had very little luck finding information to resolve this issue. Everthing seems to work fine and there are no errors in the Event log. Any suggestions as to where to start troubleshooting?

So Exchange is installed on a DC? If so, Exchange will only use itself for DSAccess and will not fail-over or use any other DC. That may explain that. In fact, ExBpa should alert on that.

I agree with Andy. Several Exchange Server directory components, such as Directory Service Access (DSAccess), Directory Service Proxy (DSProxy) and the Message Categorizer will not fail over to any other domain controller or global catalog server. This Exchange server is also a domain controller, which is not a recommended configuration http://technet.microsoft.com/en-us/library/aa997407(EXCHG.80).aspx Regard, Xiu

Okay, but why did the BPA Health Check previously provide me more info regarding the server and now it just returns this error and no other additional information?

Not sure. Updated exbpa xml file maybe, or updates that have been applied to the server perhaps.