No sound except system sounds 16.04
Solution 1:
I think that the issue is with the pulseaudio configuration files. They are somehow messed up.
I had the same problem with my linux Ubuntu 18 and I searched online for a long time until I found the answer.
The easiest and most effective solution is that you delete all the configuration files for pulse (pulseaudio) and then restart pulseaudio.
type the following code in the terminal:
rm -r ~/.config/pulse*
pulseaudio -k
Hope it helps!