I am receiving the following error when attempting to use CTI mode in the Windows client to initiate a call from my desk phone to another internal extension: "Error occurred whilst performing a call. Possible reasons are that you are using 3CX Phone System FREE version together with a phone that does not support CTI. Contact your administrator to activate with a valid license key and try again." I reviewed the version comparison chart and it shows that the free version includes use of the CTI feature. I am using a Polycom SoundPoint IP450 desk phone. The phone setup page on the 3CX site states that this phone has limited CTI functionality but that I should be able to place calls using CTI. Is there something else that I'm missing here? Or is the documentation incorrect? Thanks in advance for the help!