Im not sure what you mean by the main voice mail port? Do you mean you have a hunt group set up and the first port in the hunt group fails to answer but the other ports answer OK?
What voice boards/interface are you using? Dialogic?
One thing thats caused Dialgoics TAPI driver some problems in the past is having dialouts and incoming calls banging away on the same port. There were some timing issues that caused them fits and it would essentially never put the port back into service. If you have some ports set for dialout (i.e. analog lamps, TRAP connections, pager and message delivery dialouts), try to move those to the end of the hunt group (assuming its a first available hunt scheme) which will minimize the time outbound calls are being made on a port at the same time an inbound call is being answered.
That aside, if its the Dialogic TAPI driver is getting wedged, wed want you to turn on some diagnostics for their driver and get that information to us to pass on to their support team. Your best bet right now is to call our support folks and get that ball rolling.
Jeff Lindborg
Unity Product Architect
Active Voice
jlindborg@activevoice.com
http://members.home.net/jlindborg