HDMI sound not working after upgrading to 20.04

After upgrading to ubuntu 20.04 the hdmi sound stopped working. If I select headphones as audio output they work well, but if I change to HDMI output it doesn't work.

Also I noticed that when I select HDMI output the "configuration" option disappear.

If I select headphones as output, the configurations look like this:

when I select HDMI output, the configurations look like this:

And no sound is played.

What can I do to fix this?

Reboot should not be necessary if you just need to reinitialize pulse, just do a:

killall pulseaudio; rm -rf ~/.config/pulse/* ; rm -rf ~/.pulse*

and you should be good as well.

Suggestion of Raffa works for me on a laptop Asus UX303L !

rm -r ~/.config/pulse/
reboot

and it's ok now

Reboot with the HDMI connected, I had that "bug" or fail, and restarting with the HDMI connected Ubuntu detects the sound, but if you connect the HDMI after the start, it doesn't. It happens since 20.04 (not on 19.10). This is just a workaround.