There are two ways to mute the VDV web interface.
The simplest method of muting the interface is through the web browser (i.g. Firefox, Chrome), Right-click on the browser tab, containing VDV and select Mute Tab. This will only mute that tab for as long as it is open.
The user account within VDV can also be muted, and VDV will remember the settings for subsequent logins.
To mute the user, click the user icon in the top-right corner of the screen.
That will open a ribbon menu on the right side of the screen. From that menu, press the speaker icon. The button will turn red, indicating that the system has been muted.
To unmute, press the button again, and it should revert to its original color.