Flashing White: When the dock is first connected to power, the LED will flash white three times.
Solid White: When Fire HD 8 Plus is docked and charging wirelessly, the LED will turn solid white while it’s charging. When charging is complete, the LED will turn off.
Flashing Red: Foreign Object Detection has initiated
What is Foreign Object Detection?
To ensure the safer operation of the Wireless Dock, if an object not meant to be charging is detected (for example, a coin, paperclip or other metal object), the Wireless charging transmitter will detect the foreign object and stop charging.