We changed from a MM 5.2 TDM connection to a SIP connection this summer and I don't know if this issue is related or not but it seems to have started around the same time. I have 9 800 #'s of which 6 work properly. The 3 that don't work do get routed to MM but after 4 seconds of hearing the voicemail message the calls get disconnected with a fast busy. Does anyone know if this might be related and if so how I can fix these lines?