Hello, you should check * check realm parameter on function * check user information in hss even if there is a nonce paremeter in auth header , it always gives this error. Yasin CANER ________________________________ From: sr-users <sr-users-bounces(a)lists.kamailio.org> on behalf of Woscek, Martin W. <mwoscek(a)mitre.org> Sent: Thursday, May 2, 2019 2:30 AM To: Kamailio (SER) - Users Mailing List Subject: [SR-Users] Kamailio 5.2.2 IMS authorization failed by the SCSCF Hi, We are getting a SIP 401 Unauthorized -Challenging the UE error originating by the SCSCF. It looks to be related to the nonce/cnonce. Is there something we have misconfigured in our SCSCF module? Log output: May 1 14:01:45 imskamailio /usr/local/sbin/kamailio[18489]: DEBUG: ims_auth [authorize.c:786]: authenticate(): Nonce or response missing: nonce len [-108158976], response16 len[1873606560] May 1 14:01:45 imskamailio /usr/local/sbin/kamailio[18492]: DEBUG: ims_auth [utils.c:168]: get_nonce_response(): Calling find_credentials with realm [ims522.irisims.org] May 1 14:01:45 imskamailio /usr/local/sbin/kamailio[18492]: DEBUG: ims_auth [utils.c:195]: get_nonce_response(): Found nonce response May 1 14:01:45 imskamailio /usr/local/sbin/kamailio[18492]: INFO: ims_auth [authorize.c:827]: authenticate(): uri=sip:irisims.org nonce=9863c63855c8dd888c5c18e79fc61156 response=ce7ce73872b92aff2defa76dd1aff1ac qop=auth-int nc=00000001 cnonce=4fe4daacd69fa3d609c8b396d331eae6 hbody=d41d8cd98f00b204e9800998ecf8427e May 1 14:01:45 imskamailio /usr/local/sbin/kamailio[18492]: DEBUG: ims_auth [rfc2617.c:135]: calc_response(): calc_response(_ha1=7a1b479a0513914e71bcd6d005b3e17d, _nonce=9863c63855c8dd888c5c18e79fc61156, _nc=00000001,_cnonce=4fe4daacd69fa3d609c8b396d331eae6, _qop=auth-int, _auth_int=1,_method=REGISTER,_uri=sip:irisims.org,_hentity=d41d8cd98f00b204e9800998ecf8427e) Thanks, Martin