[2019] f keys not working

First try to reset your keybindings ingame and try again

by any chance your using a net or notebook or a keyboard with a FN key ? If so check if FN is active or not and check again ingame if they still don't work try on desktop

ctrl+shift+num

if this isn't working try FN+numlock or only numlock on some devices also Numlock+F11 can help