Hi Arturo, are we talking about the same site that Juan has mentioned?
It looks like you’re loading the Font Awesome 5.0 stylesheet via one of GP’s hooks. Hence deactivating it removes the hook and the FA 5 icons being used in the footer.
Whilst FA 5 is installed you cannot use Elementor FA icons as they are the old 4.7 and (in particular) the social brand icons require a difference class name.
So the current solution is to replace the Social Icons in the footer with a FA 4.7 version.