A power outage or router service interruption disconnected the bulb from the network. While the bulbs do not need to have constant power, if the bulb does lose any power for a long duration of time, it might need a SOFT RESET. In order to do that, do not remove the bulb from the app. Just select the plus sign on the main menu in the top right-hand corner of the screen. Add the bulbs with the original steps, and all names and schedules given will remain and bring your bulb back to a functional state.
For additional instructions please visit the user manual. You can also watch this video for information about how to install your light bulbs.
