Need add _tmx_tmb.prepare_to_cancel(t, &cancel_data.cancel_bitmap, 0); into function static int t_cancel_branches_helper(sip_msg_t* msg, int n) at case of 2( "this") proposed changes: ``` case 2: /* prepare cancel for current branch (idx) */ if(msg->first_line.u.reply.statuscode>=200) break; cancel_data.cancel_bitmap = 1<<idx; + _tmx_tmb.prepare_to_cancel(t, &cancel_data.cancel_bitmap, 0); break; ``` ### Additional Information kamailio version 4.* to 5.* ``` ``` Without this it can't cancel "this" transaction. Rare case due to low use of "this". -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://github.com/kamailio/kamailio/issues/1620