Make sure the Bluetooth of smart phone is ON, and smart phone OS Android 4.4 & Above, iOS 8.0 & above.
Make sure the distance between phone and device is within 0.5 meter; device is among the normal Bluetooth communication distance range (Within 7 meters) after pairing finished.
Make sure the device is not under low battery. If there is still a problem after fully charged, kindly raise a support ticket to support@actofit.com