Can't reset encryption key, Powerline 2000

I am unable to create a new encryption key between my 2 Powerline 2000 devices by following the instructions in the user manual.

The user manual states:   "Press the Security/Factory Reset button on the first PowerLINE device for two seconds.
The Power LED starts blinking after you release the button, and then the PowerLINE device automatically
creates a new, randomly generated encryption key that all other PowerLINE devices on the network will
use.  At this point, the PowerLINE devices cannot communicate with each other."

When I press the Security/Factory Reset button for 2 seconds, and then release it, the Power LED does not blink.  I can press the reset button for any length of time:  2 seconds, 10 seconds, 30 seconds, but when I release the button nothing happens.  Contrary to what the manual states, the power LED does not blink, and the two devices do not stop communicating.

I have attempted the process multiple times, sometimes with client devices connected and other times without client devices connected.  I have attempted the process on both of my PLP2000 devices, the one connected to my router and the other one connected to my client PC.  In all cases, pressing the reset button for any length of time does nothing.

So I am unable to detemine if my PLP2000 devices are secured or not, and following the user manual instructions does nothing.

Apart from this, the devices are working very well.

Please advise with information on how to get this process to work.  Also helpful would be information on how to verify that a new (non-factory-default) encryption key is in use.  Thanks.