Why does it tell me my extension is already in use?
Many times agents can be confused about this as it will tell you all X-Lite extensions that are already in use and agents will think that means that there's is in use. Please make sure that the agent's extension is not actually in the drop down menu.
However when this does happen it is because two agents have the same extension open on two different X-Lite phones on two different computers. This is common if an agent works from home and the office and forgets to close down the X-Lite at one location. Please check all X-Lite phones and verify that no one has the same extensions assigned to them.