UI - Button doesn't highlight using the mouse

Hi!

I am curretly working on the main menu of my game and I have a problem with my UI elements, they work fine when using the keyboard but if I click on them with the mouse, the game get stuck, it turns out to be impossible to click on any button anymore and the keyboard doesn't work. I think there is a conflict between the keyboard and the mouse, I would prefer to use the keyboard anyway but it would be nice to fixe this bug hahaha

Anyone has a clue?