Mouse problem

I have a gaming mouse with two buttons on the side (right above my thumb) and I've binded two actions to these buttons. However, I recently played a game and tried to press these buttons but they don't seem to work. I tried looking into the hotkey settings in the menu and no luck. So then I thought these buttons might've broke or become unresponsive. So after that game, I tried using these buttons in a new window on google or whatever and I usually use these buttons to go back and forward pages so I don't have to physically click the arrows at the top left to go back or forward, and the mouse buttons worked fine. I tried going back onto league and going into training mode to see if the buttons would work again but no success. It seems that the buttons don't work only on league for some reason. I've tried unplugging my mouse and plugging it back in and I've messed around with the hotkey settings but nothing seems to work. If anyone else has had this problem, any help would be appreciated. :)