[SOLVED]Fade in Fade out problem

Hi, I have a fade In - fade out script which is working fine in another project however in this project it seems the fade out fail to cover the buttons like in the picture attached

Anyone have any idea why is this happening ?

It was the sort order of the canvases. I had fade canvas on sort 0 and menu canvas on 999 and it must be vice-versa:
menu 0 fade canvas 999