Diagnosis
The bulb has lost its connection to your Wi-Fi router. This is typically a signal strength or router configuration issue, not a bulb fault.
How to Fix It
Check the bulb's signal strength in the Tapo app under Device Settings. If it's fair or poor, improve placement. The primary fix is to ensure your router's DHCP lease time is not set extremely short (under 1440 minutes). Reboot your router to clear any connectivity glitches, then reboot the bulb via its physical switch.
If That Didn't Work
Interference from other smart devices or dense Wi-Fi congestion can cause drops. In your router settings, change the 2.4 GHz channel to 1, 6, or 11 to avoid overlap with neighbors. Ensure the bulb's firmware is updated in the app.
Heads Up
Routers that combine 2.4/5 GHz into a single SSID (band steering) often cause these drops. Splitting them into separate network names is the most reliable permanent solution.