If it is still searching for the base it sounds as if its not paired, or it's set to look for a different base station.
Your instruction manual should tell you how to do it but basically you need to put the base in to pair mode (usually by pressing/holding a button on the base station for a few seconds) and then on the phone go into the setup and "pair". Some link straight away, others still need you to type in a security code (default is usually 0000 or 1234). Check your manual for details.