Play/Pause, rewind and fast-forward buttons aren't working
F7, F8, and F9 used to working in and out of any application for iTunes. However, when I tried to pause or play music from safari, it would start controlling the video, so I would have to leave the app then pause it on iTunes. Now, it has stopped all functions and will not work whoever ever I press them. Please help, this is very frustrating.
MacBook Air, iOS 11.2.5, Keyboard