I have Unity 4.X intergrated w/CM 4.x on MGCP gateways. When an outside call from PSTN goes to voice mail the subscriber gets it and can play it no problem. When a subscriber tried to call another subscriber (IP phone to IP phone)caller get busy signal and can not leave a message also if the same user tries to access VM they get a busy signal. I believe there is a SCCP prblem either between the GW/CM/Unity or CM/Unity. Which troubleshooting tool is best to use? If anyone has ran into this or has seen it please help. thanks!