m17 R5, audio mute key not working

Recently, I discovered that the audio mute key on my laptop isn't working. The button to mute the microphone is seemingly fine and glows white when pressed. However, the audio mute is unresponsive and gives no indication of muting when pressed but still glows white when the volume is manually lowered to zero. I don't think my keys are broken. Why is this? How can I fix it?