revision b21b386c050523efd369b1af1e8bee12a2ab469a
Mar 20 10:29:25 cyberdyne pulseaudio[2269]: [alsa-sink-ALC663 Analog] alsa-sink.c: Error opening PCM device front:0: Device or resource busy
Solution:
$ su $ killall pulseaudio
After that, I could play again.