This is a question for all you SIP experts on the N9.

Basically the device unregisters a little while after registering. This means that although I can still make outgoing SIP calls I can no longer receive SIP calls. It will register again if I make a SIP phone call, but then will unregister a short time later again. Basically this is as good as being useless, if I can't receive calls most of the time.

Does anyone know the solution to this? Maybe some sort of keep-alive script? I have tried changing the keep-alive settings, but it hasn't made a difference.