It’s covered up by the header. There is a box that makes up the header which has the logo and navigation menu in it. Since the background is transparent, it’s difficult to see exactly how large it is. When I hover over the bottom portion of the shop button, it changes color and allows me to click it, but higher up in the button, the color does not change and it can’t be clicked.
I would suggest using the center option for the hero content instead of the top one. That’ll move the button down a bit and hopefully will keep it out from under the header.