windows 10 – Can only select “Troubleshoot Sound Problems” but cannot adjust the volume

To clarify and narrow a previous question, why does the rocker switch to adjust the volume suddenly no longer work? Assuming this is related to an inability to select sound settings from the taskbar.

Why is it not possible to adjust the volume by clicking the speaker icon on the taskbar?

While its possible that the volume switch failed at the same time, this seems unlikely. More likely is that this a symptom for a common root cause.

While it’s possible that I’ve accidentally clicked on “troubleshoot” that’s also unlikely. More likely is that this is a symptom for a common root cause.

Why might it not be possible to adjust the volume from either the rocker button on the tablet, or by clicking the “volume” icon from the taskbar?