Ignoring INVITE
Twinkle registers just fine, and will receive calls, but after a few minutes, it seems to go to sleep and will not respond to INVITE.
Does the log show that the INVITE was received? Are you still able to call other parties after that happens?
Although I can see the INVITE arrive, the Twinkle log does not show it. However, I am able to make calls out from Twinkle.
What do you mean when you say that you "can see the INVITE arrive"? Are you watching the network traffic with Wireshark or something similar?
Yes. I am watching with sngrep on the same host as Twinkle.