This error comes up when communications between the hub and the bulb fail. Assuming you haven't reset the bulb in question (see below), there are some simple steps that should get things back up and running:
- Make sure there is power to the bulb. If your bulb won't turn on or you are unsure if there is power, check out this article.
- Make sure the bulb is in range of the hub. If things worked before, it should be in range, but if you want to be sure, try bringing the bulb to a closer socket.
- Try power cycling the bulb. Turn off power to the bulb off for 3 seconds, and turn it back on.
If you have already reset the bulb in question, it has changed its identity, and will need to be rejoined to the hub. The previous identity in the App will not work and you will receive this error. You can delete the previous identity from the hub through the Nanoleaf App and when you join the reset bulb back to the hub it will appear as a new bulb.