[SR-Users] Authentication issue during registration

Hi All I have a typical requirement, where I have a forwarding SBC between an endpoint and kamailio as shown below.

Endpoint ----> SBC ------> 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.

Next endpoint adds authorization header and sends REGISTER to SBC, SBC forwards it to Kamailio.

Now Kamailio again responds with 401.

When we analysed Kamailio logs, we can see Kamailio log authorization response token and response token that was sent by Endpoint are same.

So my question is, why Kamailio sends 401 repeatedly even if it received proper Authorization header.

Is it because Kamailio received REGISTER from IP address different from endpoint.

Please guide, how can I avoid this issue.

Thanks Austin