I have some problem with incoming SIP call, when the user pickup the call, he hear beeping sound (it might be busy signal). It doesn't happen all the time only intermittenly. The topology as below
Sip provider --sip trunk--> Cisco Cube (ISR 2911)--sip trunk--> CUCM 7.1(3)
The call comes in via DID and translated at the Cube to a hunt pilot number.
Cisco ISR 2911 is running Version 15.0(1)M1. I did not see any disconnect sip message, debug attached.
Any help will be appreciated.