Diagnosis
This is usually a simple power interruption, not a dead unit. The battery might be in a deep discharge state from shipping, or it's not making a proper connection on the charger.
How to Fix It
Let's go step-by-step. 1) Plug the USB charger into a known-good wall adapter (like your phone's) and outlet. 2) Wipe the two metal charging contacts on the bottom of the handle AND the two pins inside the charging base with a dry cloth. 3) Place the handle on the base, ensuring it's seated flat—you should feel a small magnetic pull. Leave it alone for a full 24 hours. The battery sometimes needs a long, slow wake-up charge after shipping.
If That Didn't Work
After 24 hours, try a manual reset. With the brush OFF the charger, press and hold the power button for 15-20 seconds. Then place it back on the charger for another hour and try the button. If still nothing, the internal battery or circuit is likely faulty, and you should contact support for a replacement.
Heads Up
Never use a fast-charging (QC) wall adapter. Stick with a standard 5V/1A or 2A adapter. Too much power can confuse the brush's simple charging circuit.