The status line under TapNoise in the menu shows the most common reason. Check these in turn.
- Sleeping. The Sounds switch at the top of the menu is off. Turn it on, or turn on Sounds on in Settings › General.
- Needs one permission. TapNoise can’t hear keys yet. Allow Input Monitoring.
- Unlock TapNoise to start. There’s no active license. Activate your license.
- Quiet while your mic is on. An app is using your microphone, and Quiet during calls is on. Turn that off under Settings › General › Playback if you want sounds during calls.
- The volume is down. Drag the volume slider in the menu, or check Settings › Sounds.
- Only some sounds are missing. Open Settings › Events and check Also play on. Trackpad clicks, charger and USB each have their own switch.
Sometimes the sound is quiet on purpose. Hushed is a silent-switch sound, designed to be office-safe.
If keys still make no sound after these checks, contact support with your macOS version and the status line you see.
TapNoise