Hi Paul, This warning seems to pop up every time we do a major change to the routing logic in ser.cfg :-) The warning will show up when an ACK message hits an sl_send_reply. An ACK should hit t_relay(), not sl_send_reply, which is used for reponses to INVITE. Look for a routing path where ACKs will reach your sl_send_reply and route the ACK another way... It is really easy to mix-up the routing with a small change as one have to picture how every single type of message will go through the logic. There are a lot of tests and replies that only applies to INVITEs and one solution would be to put all INVITE-related logic into a route[x] and then call the route from the main route using: if(method=="INVITE") { route(x); } There are many ways to build a ser.cfg and I haven't really seen good reference designs (i.e. how to handle different messages and segment logic into route[x]s, etc). So, you have to be able to visualize every type of message and how it will be processed (which, at least in my case, means adding a lot log(1,"reached here") entries and doing tests...) g-) Java Rockx wrote: