Why i can´t input a UI button just in a scene in particular?

Hi, i have "simple" problem with my project. I make a character selection menu using the UI buttons but suddenly does´t work. The buttos aparently are fine but i can´t click on them (i click and nothing happens, like the mouse input is not detected) and that only happens in that scene in particular.

If someone know whats happens or have any idea will be very hellpulf, Thanks for reading.