Comment 27 for bug 1403938

@i-m-jens-3)

Try the following:

1. Open the Ubuntu "settings" (use the docker or search for it)
2. Go to the sound tab
3. Select an output device you want to test
4. Click the "test speakers"
5. If it is *not* working check if the sound applet in the top bar shows the device muted
6. Un-mute it
7. Go to the browser and test a youtube video

Note that you may need to install gnome tweaks to have access to these setting options (not sure).

HTHs