Diagnosis
The red blinking light is a protection circuit error, most commonly triggered by a power surge or faulty connection. The unit has shut down to prevent damage.
How to Fix It
Perform a full power cycle to reset the internal system. This fixes it 90% of the time.
1. Unplug the soundbar's power cord from the wall outlet.
2. Unplug all other cables (HDMI, optical, etc.) from the soundbar.
3. Wait for at least 5 full minutes.
4. Plug only the power cord back into the wall.
5. Press and hold the power button on the soundbar itself (not the remote) for 10 seconds to drain residual charge.
6. Press the power button normally. It should start up with a white light.
If That Didn't Work
The problem might be the included AC adapter. Try a different power outlet in another room, and ensure you're using the original Yamaha power brick. A generic one won't supply the correct voltage.
Heads Up
If the red blinking persists after a proper reset, the internal amp or power supply has likely failed and needs service. There's no user-serviceable fix beyond this point.