The agent you are trying to intercept/barge in on, are they on an inbound ACD call? If so, are you clicking on "Inbound" under their name?
Also, barge and intercept are only availabe on Enhanced and Premium license. See page 25 and on for what is available for each license type.
The icon in your image indicates it is not the "Inbound" but instead the "Logs" that you are on. Do you see an icon like selected in the below image in blue? This is where you need to be to use Barge and Intercept.
Is your CCX environment "In_Service" or "Partial_Service"? You can find out by going to the CCX App Admin page, System - Control Center. Your server(s) should be "In_Service".
Were you previously able to view this information? If so, you may want to try restarting the Cisco Desktop Call/Chat service. Per the CAD Install Guide:
The Call/Chat service acts as a message broker between the Call/Chat clients and Supervisor Desktop. It is in constant communication with all agent and supervisor desktops.
Agents’ desktops inform the Call/Chat service of all call activity. The service, in turn,
sends this information to all appropriate supervisors. It also facilitates the sending of
text chat and team performance messages between agents (excluding IP Phone
agents) and supervisors.