Your device has gone into the syncing mode, which is why it is blinking red/green. You will need to re-sync the device before it will work again.
Follow the instructions below:
1. Make sure the device is still blinking red/green. If not, hold down the main button until it is rapidly flashing green and then release. It should now blink red/green.
2. Go into the app>Device Settings (gear icon)>Delete Device
3. Under the Device List>Add a new SkyBell
4. Follow the syncing instructions.