Comment 6 for bug 1886330

I can see a few issues in the log from your VM:

1. Buggy audio in the VM's kernel driver (says pulseaudio):

jul 05 11:05:21 VM-Xubuntu-2004 pulseaudio[1406]: ALSA woke us up to write new data to the device, but there was actually nothing to write.
jul 05 11:05:21 VM-Xubuntu-2004 pulseaudio[1406]: Most likely this is a bug in the ALSA driver 'snd_hda_intel'. Please report this issue to the ALSA developers.
jul 05 11:05:21 VM-Xubuntu-2004 pulseaudio[1406]: We were woken up with POLLOUT set -- however a subsequent snd_pcm_avail() returned 0 or another value < min_avail.
jul 05 11:05:21 VM-Xubuntu-2004 pulseaudio[1406]: Disabling timer-based scheduling because running inside a VM.

2. More problems with the VM's kernel driver:

jul 05 11:05:28 VM-Xubuntu-2004 pulseaudio[1406]: Unable to set sw params: Permission denied
jul 05 11:05:28 VM-Xubuntu-2004 pulseaudio[1406]: Failed to set software parameters: Permission denied
jul 05 11:05:28 VM-Xubuntu-2004 pulseaudio[1406]: Error opening PCM device front:0: No such file or directory
jul 05 11:05:28 VM-Xubuntu-2004 systemd[1399]: pulseaudio.service: Succeeded.

3. A couple of kernel crashes apparently relating to running out of memory in the VM.

So I suggest:

  * Giving the VM more memory.
  * Running fewer apps in the VM.
  * Configuring the VM with a different type of virtual audio device (if you can).