By default, the Oracle Enterprise Communications Broker (OECB) rejects a REGISTER request from a domain for which it is not the registrar. You can enable the OECB to proxy such registration requests by way of the Proxy Registrations control in the SIP Interface configuration.

In the SIP Interface configuration, select Proxy Registrations to tell the OECB to proxy the registration towards the intended registrar. When you deselect Proxy Registrations, the OECB responds with a 403: Unauthorized message.