06-10-2018 01:58 PM - edited 06-10-2018 02:00 PM
I had the same problem. I turned on and off the power several times, uninstalled app and nothing worked.
Finally, I discovered there are 2 tiny, almost hidden, buttons on the lower part of the switch. On the lower left is:
on the lower right is:
If you hold the wi-fi reset button for 30 seconds or longer all the saved settings, including the wi-fi settings will go back to factory default, effectively forgetting all the WI-FI settings.
You will then be able to connect to the light switches own mini wifi with your phone.
It creates it's own mini wifi for the first 30 seconds or so after powering on, known as the "admin wifi". You have to connect to it in order to then set up your connection from the switch to your home wifi. Until you connect administratively with the app the switch won't be able to change any settings to your home wifi (this was due to my having upgraded my home wifi router and network settings that had changed).
This article describes how to reset to factory defaults
there's a page on their site that details some of this, although not quite as explicitly as what I've outlined here.
Attached is the picture