Function keys not working on Magic Keyboard
I have a new Magic Keyboard paired to a MacBook Pro (13in 2020). The function keys worked fine, but since I charged the keyboard they now don't work.
F11 (which should turn the volume down) now hides windows. None of the others do anything at all.
When I go to Preferences > Keyboard and select "Set Up Bluetooth Keyboard" nothing happens - it just spins and spins. But I'm using the keyboard right now, so it is connected.
Any suggestions? I've restarted my MacBook and turned the keyboard on and off.
Thanks
MacBook Pro 13″, macOS 10.15