My Hue Bridge was working for about 2 years. One day I found that I couldn't connect it. Looking at the device I can see that the third light (internet) is off, and it doesn't show up in the Hub 3's list of connected devices. I've tried various things:
Power cycling the Hue and the Hub 3
Factory reseting both devices
Running the Hub 3 diagnostic tool
Switching ethernet ports
Assigning a static IP to the Hue Bridge
Interestingly, if I run the Hub 3 diagnostic tool, the following happens:
"Philips-hue" reappears in the list of connected devices.
The 3rd light (internet) is now on and solid
As soon as I use the Hue app to try and connect to it again, the device is booted off the Hub3's devices list.
At which point the 3rd light turns from solid to blinking