[SR-Users] WWW-Authenticate header Query

Hi, I am using Kamailio(4.2.5) as my SIP proxy also enabled authentication. Added two users xyz_0 and xyz_1 to the kamailio database. While Registration I am getting 401 Unauthorized as shown below SIP/2.0 401 Unauthorized Via: SIP/2.0/TCP 192.168.1.107:48601;branch=z9hG4bK858339335 From: <sip:xyz_0@192.168.1.107>;tag=251958751 To: <sip:xyz_0@192.168.1.107 &lt;sip%3Axyz(a)192.168.1.107&gt; Call-ID: 1808202998(a)192.168.1.107 CSeq: 2 REGISTER WWW-Authenticate: Digest realm="192.168.1.107", nonce="VZJ3hlWSdlr0HS/jGQljEKmY20ZrO0Qz" Server: kamailio (4.2.5 (x86_64/linux)) Content-Length: 0 The WWW-Authenticate header is not complete here, May I know the reason for this ? I am expecting algorithm, domain and other stuff in the WWW-Authenticate header. I am not able to proceed further , Please do needful. Thanks