Fn keys not working

The Fn layer is often handled inside keyboard firmware and may not produce its own browser event.

Run the check

Check whether the printed function action works outside the browser.
Review the keyboard's Fn lock or vendor utility for that model.
Test F1 through F12 in the browser where the OS does not reserve them.

Read the result

A working F key with a missing media action points to the function layer.

Limits and next step

Absence of an Fn event in the browser is expected on many keyboards.

Repeat the check after changing one setting or connection. Keep a record of what changed before deciding whether the device needs service.