[SR-Users] DISPATCHER module No destinations availables even if my Asterisk Boxes are up and running

Hello everyone. I'm using kamailio as a dispatcher in front of asterisk boxes and i use a failure route if asterisk box does not respond or send 503 error (please look at my attached kamailio.cfg) I use "ds_probing_mode", 1 and "ds_ping_reply_codes", "class=2;class=3;class=4" to OPTIONS ping the two asterisk instances but they do appear down both all the time. That is very annoying none of the INVITE go through Asterisk, they all are stopped because of my failure_route that sets no destination available ERROR: <script>: Destination down: INVITE sip:9980048587420715@XXX.XXX.XXX.XX (sip:ipofAsterisk1:5060) ERROR: <script>: Destination down: INVITE sip:9980048587420715@YY.YY.YYY.YY (sip:ipofAsterisk1:5060) ERROR: <script>: Destination down: INVITE sip:000442030044700@XXX.XX.X.XXX (sip:ipofAsterisk2:5060) ERROR: <script>: Destination down: INVITE sip:000442030044700@YY.YYY.YY.YYY (sip:ipofAsterisk2:5060) NOTICE: <script>: Media server sip:172.16.0.202:5060 failed to answer, selecting other one! NOTICE: <script>: No destination, sent 404 I don't know what's wrong with my setup, could someone give an eye to my kamailio.cfg and head me on the right track ? Thanks a lot. Seb