I have noticed strange thing related to the asterisk queue in my Elastix. I have an IVR pointing to the queue with 3 agents with "ring all" strategies. Some calls are seen in logs as "not answered" - the reason for disconnection is "congestoion". Its happens after different time period of waiting in the queue. Asterisk go to "congestoion" and disconnect caller waiting in the queue. What could be the reason of such disconnection type? System is not overloaded.