Can't mute/unmute sounds in Firefox

Phaser 3
1

Hi, how can I mute/unmute all sounds? This works in Chrome:

this.buttonSound.on('pointerup', () => {
    console.log(this.sound.mute) // always false in firefox
    this.sound.mute = !this.sound.mute;
});

But in Firefox, this.sound.mute is always false, it means, I can only mute sounds (set this.sound.mute to true).
Do you have this problem? I use the latest Firefox and Phaser 3.19.