Do you intend to use the code only for mobile? And please try re-installing your SuperFly that comes with X 4.6.4. SuperFLy has different folder names which separate them on its older versions.
The signup stopped working so I had to remove and create another one. sfm-menu-item-568. It works only in desktop now and not in mobile only as usual. I noticed the SIGN-UP item has an additional class called disabled when I inspect on the desktop. hope this helps