Cortana can't control music.

New computer that is fully updated.  On my old computer I could say, "Hey Cortana, turn down volume." and cortane would turn down the computers master volume.  When I try that now she says, "I'm sorry, I can't control your music."  ****?  Is this a bug?

That is the problem with windows as a service.  Functions that worked when it was first distributed quit working and are never fixed.   As pieces of windows are moved around, like cortana, microsoft uses it as an excuse for providing basically beta code with less functionality.  Compare photos with photo gallery, groove with windows media player, skype with lync.   every new product looks fancy and doesn't function.  

Hell, even the people/my people function has been broken for over a year, a very simple logic error and instead of fixing it microsoft develops the Your Phone application which breaks people even more.

Cortana is useless. will be until microsoft can get at least location services fixed.  But again some strategy designed to make windows tailor itself to the hardware it's  running on defeats them.  My desktop and surface tablet both have the same software but both have completely different options with both running in desktop mode.   ridiculous.  if there was a viable alternative I'd be running it..

The same problem here .. 

Cortana can't play music using Grove. 

My default music player is Grove.

The version of Cortana is Version: 2.2007.24723.0 

OS Version is Windows 10 Pro

I already search and try other things, configuring settings but it don't work.

I have the same problem with cortana, windows 10 2004 and spotify

Cortana is now an enterprise tool, not a consumer tool.

https://www.youtube.com/watch?v=O_Vd93W72WQ