[Users] calls being disconnected

Hi, I am having increasing problems with calls being cut-off after a few seconds. I'm running openser with this version: version: openser 1.1.0-notls (i386/linux) flags: STATS: Off, USE_IPV6, USE_TCP, DISABLE_NAGLE, USE_MCAST, SHM_MEM, SHM_MMAP, PKG_MALLOC, F_MALLOC, FAST_LOCK-ADAPTIVE_WAIT ADAPTIVE_WAIT_LOOPS=1024, MAX_RECV_BUFFER_SIZE 262144, MAX_LISTEN 16, MAX_URI_SIZE 1024, BUF_SIZE 65535 poll method support: poll, epoll_lt, epoll_et, sigio_rt, select. @(#) $Id: main.c,v 1.20 2006/07/04 17:25:54 bogdan_iancu Exp $ main.c compiled on 04:14:03 Aug 11 2006 with gcc 4.1.1 with mediaproxy 1.7.2 running on the same dual cpu server. At the time of the disconnect there were 100 calls going over mediaproxy (cpu at 46%), but it also happens with lower load. The pstn gateway is a Lucent Max TNT. My config is based on the onsip gettingstarted examples, except that all calls are sent over mediaproxy, by setting use_media_proxy even if no nat problems are detected: if (client_nat_test("3")||search("^Route:.*;nat=yes")){ setflag(6); ## use_media_proxy(); }; use_media_proxy(); #use mediaproxy always and: #if (isflagset(6) || isflagset(7)) { # if (!isflagset(8)) { # setflag(8); # use_media_proxy(); # }; #}; if (!isflagset(8)) { setflag(8); use_media_proxy(); }; I can attach the full config if required. I had one problem when upgrading to openserv1.1,0, that this didn't work anymore: avp_write("i:45", "inv_timeout"); in the pstn route. So this is missing, and the module section has been changed: modparam("tm", "fr_inv_timer", 27) #modparam("tm", "fr_inv_timer_avp", "inv_timeout") I tried finding the correct syntax from the latest documentation, but nothing worked. Could this be causing call disconnects? I attached a ngrep trace of a call that disconnected after a few seconds. It looks like my ua sends two ACKs to the gateway, doesn't receive a reply, and then send a bye, but I'm not sure why all that happens. Any help or pointers is appreciated. Richard