This document describes potential solutions if there are issues when you connect a Cisco TelePresence System (CTS) endpoint to a conference on a TelePresence Server.
Why am I unable to connect to a conference on a TelePresence Server with a CTS endpoint?
If a call does not connect successfully:
Ensure that the TelePresence Server is registered with a Session Initiation Protocol (SIP) registrar, such as a Cisco Video Communication Server (VCS) Control, with an appropriate domain specified. See the online help topic, System settings, for details.
Ensure that "Register numeric ID with SIP registrar" is selected for the conference that you need to connect to.