Instagram widget in footer not showing posts

Hello! I'm setting up this theme on my sandbox site and having a problem getting the CT:Instagram posts widget to show anything at all. When I configure the settings in the widget it is clear that something is amiss because it does not actually save, only spins around and around, as in this shot: https://www.dropbox.com/s/l5wrpa9cb5evhya/Screenshot%202017-10-28%2010.45.31.png?dl=0 This is my demo page: http://heartshaperock.com/wp/ Thanks for any help.