@mitu I agree with you.
I was experimenting recently on pi0 and checked the RetroFlag "patch" for their GPi Case and it has by default disabled#dtparam=audio=on applied to the config .txt which causes the exact error posted
If the # is removed and reboot the sound is back to normal.
They should update their scripts/info rather users get troubles and need to apply cmdline alsa or edit sudo nano /usr/share/alsa/alsa.confand change
defaults.ctl.card 0 defaults.pcm.card 0 to defaults.ctl.card 1 defaults.pcm.card 1