How to fix media volume stuck on zero? Today I tried to play a video but my media volume was on zero. 

I used the volume button on my phone but it did not increase the media volume. I then went to the settings --> sound --> media but I could not change the media volume from zero. 

The reason i could not change the media volume was because media volume slider was grayed out... So I could touch or change it in any way.

It's a very unintuitive problem and many others seem to have it if you Google.
Mine wasnt caused by an app.  My Do Not Disturb was accidentally set to do not disturb for anything.  Changing the settings worked.