[Serusers] Problems with ACK

Hello List. I have a problem with an ACK message for a CANCEL. I'm just wondering if anyone knows what could be happening here. It seems that SER can't route or "understand" this ACK ACK sip:0299005622408196@sipvoiss.desa.redvoiss.net SIP/2.0. v: SIP/2.0/UDP 192.168.1.100:5060;branch=z9hG4bK2861608023. f: "5502203289" <sip:5502203289@sipvoiss.desa.redvoiss.net>;tag=1349608987. t: <sip:0299005622408196@sipvoiss.desa.redvoiss.net>;tag=f146818fa4. i: 5c83a04822964085e07aabd210e9d72f(a)192.168.1.100. CSeq: 4 ACK. l: 0. Could be something with the COMPACT form ??? This is the log from the debug : Mar 23 12:18:10 sipvoiss ser[5430]: t_lookup_request: start searching: hash=52251, isACK=1 Mar 23 12:18:10 sipvoiss ser[5430]: DEBUG: RFC3261 transaction matching failed Mar 23 12:18:10 sipvoiss ser[5430]: DEBUG: t_lookup_request: no transaction found Mar 23 12:18:10 sipvoiss ser[5430]: SER: forwarding ACK statelessly Mar 23 12:18:10 sipvoiss ser[5430]: DEBUG: mk_proxy: doing DNS lookup... Mar 23 12:18:10 sipvoiss ser[5430]: get_record: lookup(_sip._udp.sipvoiss.desa.redvoiss.net, 33) failed Mar 23 12:18:10 sipvoiss ser[5430]: sip_resolvehost: no SRV record found for sipvoiss.desa.redvoiss.net, trying 'normal' lookup... Mar 23 12:18:10 sipvoiss ser[5430]: check_via_address(10.0.0.248, 192.168.1.100, 0) Mar 23 12:18:10 sipvoiss ser[5430]: Sending: ACK sip:0299005622408196@sipvoiss.desa.redvoiss.net SIP/2.0^M Max-Forwards: 10^M Record-Route: <sip:10.0.0.246;ftag=2639303304;lr=on>^M Via: SIP/2.0/UDP 10.0.0.246;branch=0^M v: SIP/2.0/UDP 192.168.1.100:5060;received=10.0.0.248;branch=z9hG4bK365542204^M f: "5502203289" <sip:5502203289@sipvoiss.desa.redvoiss.net>;tag=2639303304^M t: <sip:0299005622408196@sipvoiss.desa.redvoiss.net>;tag=2746a580a4^M i: 81983e61d980fd3ef0046dafe9518284(a)192.168.1.100^M CSeq: 10 ACK^M l: 0^M ^M . Mar 23 12:18:10 sipvoiss ser[5430]: orig. len=338, new_len=477, proto=1 Mar 23 12:18:10 sipvoiss ser[5430]: DEBUG:destroy_avp_list: destroying list (nil) Mar 23 12:18:10 sipvoiss ser[5430]: receive_msg: cleaning up What does it means : "RFC3261 transaction matching failed" and why ??? The weird situation happend when almost the same message arrives without the Compact Form : V102 ACK sip:0299005622408196@sipvoiss.desa.redvoiss.net SIP/2.0. Via: SIP/2.0/UDP 10.0.0.237:5060;branch=z9hG4bK2364391837. From: "5502203289" <sip:5502203289@sipvoiss.desa.redvoiss.net>;tag=827237367. To: <sip:0299005622408196@sipvoiss.desa.redvoiss.net>;tag=6b466391a4. Call-ID: 43b2cc325b7fbe9f8790e4cee01dc4b3(a)10.0.0.237. CSeq: 2 ACK. Content-Length: 0. This message works ok!. .... ... Mar 23 16:30:06 sipvoiss ser[5974]: DEBUG: RFC3261 transaction matched, tid=424819551 Mar 23 16:30:06 sipvoiss ser[5974]: DEBUG: t_lookup_request: transaction found (T=0x404ce3e8) Mar 23 16:30:06 sipvoiss ser[5974]: DEBUG: cleanup_uac_timers: RETR/FR timers reset Mar 23 16:30:06 sipvoiss ser[5974]: DEBUG: add_to_tail_of_timer[2]: 0x404ce430 Mar 23 16:30:06 sipvoiss ser[5974]: DEBUG:destroy_avp_list: destroying list (nil) Mar 23 16:30:06 sipvoiss ser[5974]: receive_msg: cleaning up Can someone give me a hand here? Thanks in advance Regards, Ricardo Martinez-