Hot keys won't work

It's happened a few times with a few different characters so I don't know what triggers it or anything do, but randomly while I'm in a game league will be like "I don't think we should let him use any hotkeys, he's gonna have to click on everything to use it". All I can do is use control to level the abilities up, or if I want I can hotkey them to the number pad, or space, the numbers above the letters don't work but the number pad does. Sometimes though if I mash buttons one of them will work (most of the time I end up wasting my ult when I do this). Another random thing is I can hit enter and type anything so I know it's not an issue with my keyboard or anything. Sorry I can't be more specific but this is all I know for now if I think of something else I'll post a comment on this thread. Good luck with fixing this bug.