Neatline - Base Map Layer Not Showing/Working

Omeka Version 2.8
Neatline Version 2.6.3

I am trying to use Stamen Toner as my map for a Neatline exhibit, but the map is not showing when I go into edit it or when I go to view it publicly. When I try using Google Streets, it says “This page can’t load Google Map correctly.” Why is this happening and what do I need to do to get my map working?