@JohnDBell 
Hi

The following suggestions are for your reference:
1. You could change a wall socket.
2. It is recommended that you reset the powerline extender and observe whether the light changes: Use a pin to press and hold the Reset button for at least 5 seconds to reset the powerline extender to factory default settings. When Reset is triggered properly, all LEDs will turn off and start on again.

If neither method resolves the issue, it is recommended that you contact the retailer to check the warranty.