Right and left click not working in-game

As you can see in the title, my right and left click don't work, but just in-game. I can move my mouse and outside the game my mouse works perfectly. I've tried to delete several times the folder Config, to restore settings from default, to connect another mouse, to reinstall league... But it keeps happening.

It also happened a long time ago but somehow I managed to solve it after several days, but now it happens again and I'm sick of it, I have already lost several games since minute 1 just because I can't move and I can't play the game. Please, help.