This usually indicates an issue with the wiring. Let's figure it out together: 

This is product is discontinued and replaced with the ZEN73. What does that mean?

Here's our general wiring guide for Zooz Ver 2.0 switches; the same single pole and multi-point wiring applies regardless if you have an on/off switch or dimmer. If you have the switch installed in a multi-point set-up like a 3-way, 4-way, or 5-way, make sure to refer to the relevant diagrams and try to compare your wiring to that shown in the illustrations. 

If you're unable to locate the source of the issue or you're unable to match your set up to the diagrams, take some pictures of all switch boxes involved according to the instructions shown here. Then reach out to us with the images so we can try to troubleshoot the installation remotely. 

Also, check that the switch is connected to a compatible load. Zooz shouldn't be connected to motor loads like ceiling fans, as detailed here. Improper loads like fans and home appliances may damage the switch immediately and prevent it from working correctly. If you suspect that the type of load you've connected has damaged the switch, let us know. Our team will be happy to help.