If the PL LED is red indicating good quality only, try plugging the TPL-402E into another available wall power outlet to check if you can obtain better connection quality.
Use a pin or paperclip and push and hold the Reset button for 1 second on each TPL-402E powerline adapter. All LEDs will turn off and turn back on. This will reset the TPL-402E powerline adapters to the default settings, network name/security key assignment "HomePlugAV".
Connecting the TPL-402E to a power strip or surge protector may degrade network performance or completely stop network signals.
The TPL-402E should not be used on GFI protected outlets as some outlets will filter out powerline signals.
The TPL-402E should not be used in areas with excessive heat.
Certain florescent or incandescent lights are noise sources on the electrical and can degrade powerline performance.
If your building has more than one circuit breaker box, the TPL-402E may not be able to establish connectivity between different circuit breaker boxes. In this case, connect a TPL-402E powerline adapter to a power outlet located on each of the circuit breaker boxes, and then connect an Ethernet cable between the TPL-402E powerline adapters to bridge the two circuits together.