[Serusers] SER reply 483 when register use FQDN

Hi, I just want use FQDN in my networking environment. My SJPhone use FQDN register to SER 2.0.0 but was rejected by 483 To Many Hops. However it can be registed use the same profile just replace FQDN to IP address. The DNS query process worked fine and got the right IP address. My environment elments looks like: SER 2.0.0 at host 192.168.1.120 / ipcsip.org DNS server at host 10.57.39.53 SJPhone at host 192.168.1.105 REGISTER package looks like: 192.168.1.105 -> 192.168.1.120 REGISTER sip:ipcsip.org:5060 SIP/2.0 Via: SIP/2.0/UDP 192.168.1.105;branch=z9hG4bKc0a801690000001748bf8e2a0000000000000000;rport From: "unknown" <sip:1000@ipcsip.org:5060>;tag=322515be4ca To: <sip:1000@ipcsip.org:5060> Contact: <sip:1000@192.168.1.105> Call-ID: C0AF593A85304F1D85B01F66E9CEE4680xc0a80169 CSeq: 1 REGISTER Max-Forwards: 70 User-Agent: SJphone/1.65.377a (SJ Labs) Content-Length: 0 192.168.1.120 -> 192.168.1.105 SIP/2.0 483 Too Many Hops Via: SIP/2.0/UDP 192.168.1.105;branch=z9hG4bKc0a801690000001748bf8e2a0000000000000000;rport=5060 From: "unknown" <sip:1000@ipcsip.org:5060>;tag=322515be4ca To: <sip:1000@ipcsip.org:5060>;tag=b27e1a1d33761e85846fc98f5f3a7e58.d9ad Call-ID: C0AF593A85304F1D85B01F66E9CEE4680xc0a80169 CSeq: 1 REGISTER Server: Sip EXpress router (2.0.0 (i386/linux)) Content-Length: 0 Warning: 392 192.168.1.120:5060 "Noisy feedback tells: pid=3446 req_src_ip=192.168.1.120 req_src_port=5060 in_uri=sip:ipcsip.org:5060 out_uri=sip:ipcsip.org:5060 via_cnt==18" I got same result evenif enabled dns & rev_dns in openser.cfg (dns=yes rev_dns=yes). So, What wrong with me? Coudle some give me some instructions? Best regards, Steven Wu