Input to Audacity not registering

Audacity Help Forum Windows
1

Using Windows 7. in the Sound section, Recording Devices, I have enabled “Stereo Mix”, in Communications chosen “Do Nothing”, and in playback devices, “realtek HDMI Output”
In Audacity, I chose NME, REaltek HDMI Output, Stereo Mix (Realtek High Definition), 2 Stereo Input channels

I click onto music on an internet site (youtube for example) and press the record button on Audacity.
Nothing is showing on the input meter, and no recording has been made.
I ran the tone through the transport tab, and that plays back.

What am I doing incorrectly?
CWJ

2

and in playback devices, “realtek HDMI Output”
In Audacity, I chose NME, REaltek HDMI Output, Stereo Mix (Realtek High Definition), 2 Stereo Input channels

… Just a guess, but Stereo Mix may not work with a digital output. Try it with “Line Out”, or “Speakers”, or whatever you have.