we have switched from TDM to SIP trunk. after that call forward to voicemail and also automated attendant don't work. then I changed VM pilot number to full number instead of 6000. still when inbound call is received, and called party doesn't answer the call, it is supposed to forward to VM but call is failed. also when somebody calls to main number, it is supposed forward to AA, but call is failed. very appreciate, if there is any suggestion.