We can now click on Services status, as shown in the following screenshot, to check that all system services of 3CX have started and are running correctly. If this is the case, then we have successfully installed the 3CX Phone System:

We can also take a look and see if our extensions were added correctly by clicking on Extension Status shown in the following screenshot. The Extension Status screen is an excellent place to view the status of all your extensions. We can see that our extensions were added, but we can also see in one quick glance the status of each extension:
Red: Not Registered means no phone is registered to this extension. (This is how your system should look as we didn't connect any phones yet.)
Green: Registered means a phone has been connected and registered to this extension.
Yellow: The phone connected to this extension is on a call.
If an extension is on a call, the IN/OUT column will show whether this is an incoming or outgoing call, the...