[SR-Users] ACK and BYE are forwarded statelessly (failed to parse Route HF)

Hello everyone, I have a setup where ​kamailio acts as UAC to a SIP provider. Kamailio is also configured to pass all incoming calls to an Asterisk. Here is a diagram: Phone<-->Asterisk(10.10.11.232)<--->(PRIV:10.10.11.238)Kamailio(PUB:44.44.44.148)<--->(194.213.29.92)SIP-provider. When a call comes in from the SIP-provider, it gets all the way to the phone. But when the SIP-provider sends BYE or ACK (during hungup event or 200OK/SDP asterisk response.). I get this errors in my kamailio log: siputils [checks.c:100]: has_totag(): totag found <core> [parser/parse_rr.c:49]: do_parse_rr_body(): parse_rr_body(): No body for record-route rr [loose.c:106]: find_first_route(): failed to parse Route HF rr [loose.c:929]: loose_route(): There is no Route HF tm [t_lookup.c:648]: t_lookup_request(): DEBUG: t_lookup_request: no transaction found tm [t_lookup.c:1011]: t_check_msg(): DEBUG: t_check_msg: msg id=1 global id=0 T start=0xffffffffffffffff tm [t_lookup.c:466]: t_lookup_request(): t_lookup_request: start searching: hash=10101, isACK=1 tm [t_lookup.c:424]: matching_3261(): DEBUG: RFC3261 transaction matching failed ..... .... .... siputils [checks.c:100]: has_totag(): totag found tm [t_lookup.c:1312]: t_newtran(): DEBUG: t_newtran: msg id=2 , global msg id=1 , T on entrance=0xffffffffffffffff tm [t_lookup.c:466]: t_lookup_request(): t_lookup_request: start searching: hash=10101, isACK=1 tm [t_lookup.c:424]: matching_3261(): DEBUG: RFC3261 transaction matching failed tm [t_lookup.c:648]: t_lookup_request(): DEBUG: t_lookup_request: no transaction found tm [t_funcs.c:279]: t_relay_to(): SER: forwarding ACK statelessly here is the link to: kamailio.cfg, ngrep -i any capture, debug_level6 log: http://labmir.com/kamailio/ Looking at the SIP ACK that comes from SIP provider I can see that they use strict routing. (i.e. TO field is set to kamailio's public IP that is next hop to them). Maybe I am wrong to judge that its not loose routing just because of the TO field. Anyways, because of (failed to parse Route HF) error, ACKs and BYEs are forwarded by kamailio statelessly, as a result kamailio uses wrong interface to forward them (SIP_dailog.txt line:233) and therefore asterisk never sees ACKs or BYEs. How can I make kamailio recognize ACKs and BYEs belonging to a dialog and pass them statefully through the right interface? It is worth to mention that I use exactly the same config with a different SIP-provider (which is peered to our PUB IP not registered through UAC like in this case) and it works flawlessly. Thank you, Mir