We are in the process of testing the Unified Messaging capability of Exchange 2010 and hope to implement it soon. We have found that for certain users the MWI works and some users it does not. I am able to turn up diagnostic logging on the Exchange server and can see the MWI being set when it works and I see no MWI related events at all when calling users where the light does not come on. Because we can see that Exchange is able to send a MWI successfullly to the PBX in some instances, we know that this is not an issue with the PBX. If it were, we would likely see MWI failure messages in the event log. It seems as if Exchange is not attempting to set the MWI at all. Or at least there is no record of it trying for certain users. Do you have suggestions? Or at the very least, can you tell me which other logs, besides the ones marked as UM, would be useful to turn up the logging level?
Thanks. Any help is appreciated.