BlackWidow V4 F11 Not working for full screen and window

I have been using this keyboard for around a month now and for some reason the F11 key stopped from changing from full screen to window I try testing if the key is broken or something but it works just fine 

I know not being able to changing from full screen to window is not a big deal but I’m losing my mind and I cant find anyone with the same problem on internet I would love to know if someone have a solution for this problem