Every time I hit the F5 or F6 to light it up, A grey box pops up with a cancel sign in the bottom and won‘t let me light up my screen. What buttons do I hit to unlock it?
Macbook Pro Keyboard Light
If you are in a bright place, it will do that if the Auto illumination is checked. Try going to System Preferences/Keyboard and un-check Automatically illuminate keyboard in low light
