Moved to Help & Support/Errors & Bugs

 

Is your microphone plugged in?
Do you have a USB microphone that requires a driver?
Do you have the microphone as the default input device? (right click the sound tray icon on the bottom right and click input devices)

 

Where it says input device chande that to frontmic if you have that option. Also you must hold down the up button to talk. You will hear a noise to identify that you are transmitting. To change which button to push, click in the box where it says keyboard: up then hit the desired key then click ok.

 

Also make sure you don't have either "mute" button checked at the bottom of the main screen. Sounds simple but I think most people have done that at one point or another.