(1) Swap the two red wires and the black wire one by one.
(2) If the same problem persists or the 3-way dimmer switch doesn't work, try installing it on the other side as the side where this switch is installed may not be the power side.
(3) If the issue still persists, please send the detailed information about the problem and the photos of the wiring diagram of the old switch to our support team at support@treatlife.tech for further assistance.