Hi Daniel, thanks for your attention! Regarding the tests you suggested, we ran all changes individually and both dm_worker and worker_usleep didn't work and problem still happened. The track_cseq_updates is still under test but is already running for 7 hours without having the issue. Usually the freeze was happening within the first 2 hours of test. Also considering the previous analysis we've done, we can see the function dlg_cseq_msg_sent is being called when the dead lock happened, so I guess this is a strong evidence there is something wrong with this feature + DMQ? Also I saw this commit https://github.com/kamailio/kamailio/commit/a309a0ee48278923871197391a30d485... from yesterday, is this potentially a fix for this problem?