[SR-Users] Unable to parse the Cancel request

Hello, We are having an issue here where Kamailio is complaining about duplicate To header, while in the SIP Packet there is just one. See below the log message: DEBUG: tm [t_msgbuilder.c:391]: build_local_reparse(): duplicate To header ERROR: tm [t_msgbuilder.c:531]: build_local_reparse(): cannot build CANCEL request ERROR: tm [t_cancel.c:297]: cancel_branch(): attempt to build a CANCEL failed ERROR: tm [t_fwd.c:1434]: e2e_cancel(): cancel error And this is the sip message: CANCEL sip:123456789@1.2.3.4:5060 SIP/2.0 Via: SIP/2.0/UDP 192.168.1.1:19373 ;branch=z9hG4bK-524287-1---7774073fad1a3264;rport Max-Forwards: 70 To: <sip:123456789@1.2.3.4:5060> From: "101"<sip:101@1.2.3.4:5060>;tag=6f373b66 Call-ID: hC2O6zx8ZaUJ1di046 CSeq: 2 CANCEL Proxy-Authorization: Digest username="101",realm="1.2.3.4",nonce="YJKbfWCSmlFTHxdJfKmySydF9L7FzfaqcgyOo4A=",uri=" sip:123456789@1.2.3.4:5060 ",response="2bf2ba8ef2374d6aa8c39d650613077d",algorithm=MD5 User-Agent: TEST Content-Length: 0 version: kamailio 5.5.0 (x86_64/linux) d4c1a1 The route itself, is like in the standard documentation: # CANCEL processing if KSR.is_CANCEL() : KSR.info(RANDOM_LOG + 'KSR.is_CANCEL') if KSR.tm.t_check_trans()>0 : self.ksr_route_relay(msg) return 1 def ksr_route_relay(self, msg): if KSR.is_method_in("IBSU") : if KSR.tm.t_is_set("branch_route")<0 : KSR.tm.t_on_branch("ksr_branch_manage") if KSR.is_method_in("ISU") : if KSR.tm.t_is_set("onreply_route")<0 : KSR.tm.t_on_reply("ksr_onreply_manage") if KSR.is_INVITE() : if KSR.tm.t_is_set("failure_route")<0 : KSR.tm.t_on_failure("ksr_failure_manage") if KSR.tm.t_relay()<0 : KSR.sl.sl_reply_error() return -255 Thanks