First, make sure you have the latest version of Logitech Options+ software installed. You can download it here.

The mute and unmute microphone feature of your device can only be enabled once you have installed the software.

Mute/unmute microphone works on a system level, not on an application level. When you press the key to mute, you will see the image shown on the top right corner of your screen.

This means your system’s microphone is muted. If you are unmuted on a video conferencing app (ex. Zoom or Microsoft Teams) but can see this sign, you will not be heard when speaking. You’ll need to press the mute/unmute key once more to be unmuted.