I’m facing an issue where calls to confbridge on an asterisk are dropped with an error of “no reply to our critical packet”. Several calls work fine, then (seemingly after exceeding a certain number of calls) all calls are dropped almost simultaneously.
As fas as I was able to trace it seems, that the UCS is responding to a session-timer refreshing Re-Invite, but asterisk is not sending an ACK for the response, instead retransmits the re-invite. After some timeout the call is then dropped. This then happens to all the other active calls.
Any help in finding out what causes the problem would be very much appreciated.