If you changed the password of your WiFi Router on each gang on the app will appear a sign of no connection.
To restore the connection remove the faceplate from your iotty Light Switch and with a small object (such as a paperclip) press the AP button (as shown in the image).
Go to My devices on the app and click on the + you find up on the right and follow the procedure.
In case you already did a registration in the past, once you restore the connection you’ll find all the preferences as you set them.
Then after you attached the face plate restart the device from the device setting on the app in order to re calibrate the touch.