3CX uses "services" to run the software. A computer service is a program that runs without anyone launching it. Internet Explorer and MS Word are NOT programs that run as a "service", as you need to log on to the computer and double-click the program to launch them for use.
These services will run all the time (as long as the computer is on, of course) without anyone touching them. 3CX relies on 12 such services to operate its every feature.
In the left-hand window, click Services status, and you will see the following screenshot:
This screen shows you all the services that are installed and if they are running or not. If you cannot make a conference call, make sure this screen shows you that the Conference Room service is Running. On the top, you have controls to Start, Stop, Restart (stop the service and then automatically start it), or Restart All.
If you are experiencing trouble with 3CX, restarting the services can usually fix the problem. It's the...