[SR-Users] Registration at SCSCF Failed

Hi All In 4.2.0 Kamailio (S-CSCF), when I try to register an IMS endpoint, I get 403 from P-CSCSF. When I checked the error logs, SCSCF logs look as below 1(5455) INFO: ims_auth [authorize.c:824]: authenticate(): uri=sip: group4-imslab11.in nonce=b9eec0ad9d6d186408541d8a23a7c7a5 response=df89adebbf28f25d38d2f993f7cde033 qop= nc= cnonce= hbody= 1(5455) INFO: ims_auth [authorize.c:872]: authenticate(): UE said: df89adebbf28f25d38d2f993f7cde033 and we expect df89adebbf28f25d38d2f993f7cde033 ha1 599fb074cf189867eed06f3b6ebc0b97 (REGISTER) 1(5455) INFO: ims_registrar_scscf [cxdx_sar.c:79]: create_return_code(): created AVP successfully : [saa_return_code] - [-2] 12(5466) INFO: ims_registrar_scscf [cxdx_avp.c:138]: cxdx_get_avp(): cxdx_get_experimental_result_code: Failed finding avp 12(5466) INFO: ims_registrar_scscf [cxdx_avp.c:138]: cxdx_get_avp(): cxdx_get_charging_info: Failed finding avp I have added an user necs_0 in hss_db, so why I get below error. Please let me know what is missed here. Is S-CSCF not able to contact HSS ?? Best Regards kamal