There are several possible causes. Please make sure to eliminate following factors.
(1) Step on scale barefoot. Do not wear socks or shoes.
(2) Each foot needs to touch two metal pads, all four metal pads needs to be touched.
(3) When weighing do not get off the scale too quickly. Stand still until the measurement complete. First you see your weight will flash twice on your scale, then number “0” moves back and forth. When the “0” stops moving and your weight appears again, your measurements are done.
(4) Make sure the metal pads on the scale platform are clean. You can use damp cloth to clean.
(5) If you have dry feet or callus on your feet, it may affect the conductivity. You can use damp cloth to wipe your feet.