Our BT8600 system has two handsets plus the previously existing corded handset, which still functions as part of the phone system, but not using the Call Guardian system. The three handsets have functioned fine for several years, but now, when there is an incoming call, sometimes (not consistently) the BT 8600 handsets will not pick up the call, and the display shows 'Line in use- a call cannot be made'. If this happens, the call can only be picked up on the old handset. Any ideas how to cure this?
