Hamburger Menu wont expand or react in mobile only

[wixiemrs]

My site is prettyinpink.ie, yesterday without any changes being made, my hamburger menu stopped reacting / dropping down in mobile only. Web works fine, its displaying the menu options and they are clickable. In mobile, when the hamburger icon is displayed it doesnt do anything when clicked. 

When reviewing the settings i see toolbar > Navigation and an error ' This menu won't show dropdown items' but no instructions or options to fix this. Any help is appreciated