On the phone page, check the auto line selection to make sure you have the right option (typically in/out). After that make sure the user is not pressing the button on the phone instead of just picking up the receiver, and also, check the hook switch, to make sure it lifts when the handset is picked up. On some older phones, they had a weak spring that would end up not being strong enough to lift the hook switch button, leaving the phone in handsfree.