1. The phone needs to support Bluetooth 4.0(Bluetooth Low Energy). Most newer devices have that but you might try the manufacturer if you are not sure. For example some phones that do work are: iPhone 5 or newer, Samsung GS5 or newer.
2. If the phone does have Bluetooth 4.0 make sure it is turned on from the phone settings.
3. The feeder must be turned on.
4. If the feeder is connected to ANOTHER phone or tablet it must be first disconnected before it connect to a new phone or tablet. i.e the feeder can only be connected to 1 phone at a time.