请问题个sip INVITE 401 的问题......

Question

INVITE sip:1029@192.168.0.163 SIP/2.0^M
From: <sip:1027@192.168.0.30>;tag=a46afd68-fa74-4540-a805-a819d93a7798^M
To: <sip:1029@192.168.0.163>^M
Call-ID: 4ac7bd33-abda-4202-bb0e-54495a96ba48^M
CSeq: 1 INVITE^M
Via: SIP/2.0/UDP 192.168.0.30:5060;branch=z9hG4bK-5a21-16013c8-2f24a697^M
Contact: <sip:1027@192.168.0.30:5060>^M
User-Agent: X-Lite release 1105x^M
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY, MESSAGE, SUBSCRIBE, INFO^M
Max-Forwards: 70^M
Content-Type: application/sdp^M
Content-Length: 144^M
^M
v=0^M
o=RS 123456789 123456789 IN IP4 0.0.0.0^M
s=Sip Stack^M
t=0 0^M
m=audio 3333 RTP/AVP 0 8^M
c=IN IP4 192.168.0.99^M
a=rtpmap:0 PCMU/8000

SIP/2.0 401 Unauthorized^M
From: <sip:1027@192.168.0.30>;tag=a46afd68-fa74-4540-a805-a819d93a7798^M
To: <sip:1029@192.168.0.163>;tag=0-13c4-4bfd4440-15e81b14-d78^M
Call-ID: 4ac7bd33-abda-4202-bb0e-54495a96ba48^M
CSeq: 1 INVITE^M
WWW-Authenticate: Digest realm="000362807DDF",nonce="80ccdfdc80df",opaque="SIP37XY",stale=true,algorithm=MD5,qop="auth"^M
Via: SIP/2.0/UDP 192.168.0.30:5060;branch=z9hG4bK-5a21-16013c8-2f24a697^M
User-Agent: IP PBX^M
Content-Length: 0^M

ACK sip:1029@192.168.0.163 SIP/2.0^M
From: <sip:1027@192.168.0.30>;tag=a46afd68-fa74-4540-a805-a819d93a7798^M
To: <sip:1029@192.168.0.163>;tag=0-13c4-4bfd4440-15e81b14-d78^M
Call-ID: 4ac7bd33-abda-4202-bb0e-54495a96ba48^M
CSeq: 1 ACK^M
Via: SIP/2.0/UDP 192.168.0.30:5060;branch=z9hG4bK-5a21-1601417-6afb7d67^M
Contact: <sip:1027@192.168.0.30:5060>^M
Max-Forwards: 70^M
Content-Length: 0

INVITE sip:1029@192.168.0.163 SIP/2.0^M
From: <sip:1027@192.168.0.30>;tag=a46afd68-fa74-4540-a805-a819d93a7798^M
To: <sip:1029@192.168.0.163>^M
Call-ID: 4ac7bd33-abda-4202-bb0e-54495a96ba48^M
CSeq: 2 INVITE^M
Via: SIP/2.0/UDP 192.168.0.30:5060;branch=z9hG4bK-5a21-1601418-72893a75^M
Authorization: Digest username="1027",realm="000362807DDF",nonce="80ccdfdc80df",uri="sip:1029@192.168.0.163",response="86673082470cd18f01df5999ab2b2098",algorithm=MD5,cnonce="9639a2fac8b785312bd4980409444096",opaque="SIP37XY",nc=00000001,qop=auth^M
Contact: <sip:1027@192.168.0.30:5060>^M
User-Agent: X-Lite release 1105x^M
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY, MESSAGE, SUBSCRIBE, INFO^M
Max-Forwards: 70^M
Content-Type: application/sdp^M
Content-Length: 144^M
^M
v=0^M
o=RS 123456789 123456789 IN IP4 0.0.0.0^M
s= Sip Stack^M
t=0 0^M
m=audio 3333 RTP/AVP 0 8^M
c=IN IP4 192.168.0.99^M
a=rtpmap:0 PCMU/8000

SIP/2.0 400 Bad Request^M
From: <sip:1027@192.168.0.30>;tag=a46afd68-fa74-4540-a805-a819d93a7798^M
To: <sip:1029@192.168.0.163>;tag=0-13c4-4bfd4440-15e81b14-d78^M
Call-ID: 4ac7bd33-abda-4202-bb0e-54495a96ba48^M
CSeq: 2 INVITE^M
Via: SIP/2.0/UDP 192.168.0.30:5060;branch=z9hG4bK-5a21-1601418-72893a75^M
User-Agent: IP PBX^M
Content-Length: 0

请问大家为什么回 400 哪 ， 我哪个地方错了.......
非常感谢.......