AustinThanksCan that cause Kamailio to challenge it repeatedly.One of the reason I suspect is, in my case for REGISTER message to uri and from uri are different.I took SBC from my test scenario.Then I found same issue, Kamalio challanges repeatedly.On Mon, Sep 14, 2015 at 11:22 AM, Austin Einter <austin.einter@gmail.com> wrote:Is it because Kamailio received REGISTER from IP address different from endpoint.So my question is, why Kamailio sends 401 repeatedly even if it received proper Authorization header.When we analysed Kamailio logs, we can see Kamailio log authorization response token and response token that was sent by Endpoint are same.Now Kamailio again responds with 401.Next endpoint adds authorization header and sends REGISTER to SBC, SBC forwards it to Kamailio.From endpoint I am sending REGISTER request. It reaches SBC. SBC sends the REGISTER request to Kamailio, Kamailio challenges it (401), and challenge response is received at endpoint through SBC.Endpoint ----> SBC ------> KamailioHi AllI have a typical requirement, where I have a forwarding SBC between an endpoint and kamailio as shown below.Please guide, how can I avoid this issue.ThanksAustin