Using KDE: After the upgrade, my Firefox doesn't play any sound. Fist I notice this in youtube, but I can't play any sound in other sites that play audio+video.
I can play video+sound in other browsers: chrome, waterfox and any other application: smplayer, vlc, spotify.
This is the current setting in autoplay, but before was "Allow Audio and Video" to all sites and still the issue occurs:

The DRM is checked:

In some websites playing videos shows the speaker on but no sound:

I wonder if there is a key "shortcut" in the browser that has disabled the sound in the whole browser.
Maybe it's just me because I can't find any report about this issue. Any hint?
Thanks!
I found it!, clicking the icon in the task bar "mute" the whole browser
:
Very useful feature, but make me lost my Sunday seeing videos
at home.
