Viva supports multiple brands of smart bulb devices, which can simply replace normal bulbs to make them smart.
Those bulbs will turn ON/OFF depending on if they have power or not. To allow it to be controlled by the smart home system, those bulbs need to be powered all the time. Without power, they simply cannot be switched remotely.
We suggest to control those via the smart home app or let it be automatically turned ON or OFF instead of using the physical switches as those may interfere with the system.
If a bulb is not responding to app interactions, make sure it's powered and has not been switched off manually before.