CSTA requires licensing as I recall. It was always necessary with ESNA voicemails (Telephony Officelinx) so could be part of your problem here. It was used by the TOL for signalling MWL changes and the like. If it failed, we usually just forced it to use voicemail ports with in band signalling as if it was a Legacy type voicemail system

Sometimes the thoughts in my head get so bored, they go for a stroll through my mouth. This is rarely a good thing.