If the Computer Telephony Integration (CTI) Route Point (RP) is not connected to any application (like any Java Telephony Application Programming Interface (JTAPI) application, Customer Response Applications (CRA) or Customer Response Solutions (CRS)), it indicates Unknown for registration. This issue can also occur if you have added the CTI route point to the hunt group. A CTI route point is not supported as a member of the hunt group. A hunt group member must have a directory number, phone or voice mail.
Also, if the CTI route point is forwarded to voice mail, it is in Unknown state, since it is not in a line that can be monitored by Telephony Call Dispatcher (TCD) to be idle or busy.
To resolve the issue, perform this procedure:
If you are using RP for Auto Attendant (AA) or Integrated Call Distribution (ICD) application, make sure that you have the JTAPI user associated with the RP, then reset the RP to get registered to Cisco CallManager.