@AlexManyeki, sorry to both you again with this. I'm trying to get this to work.
First of all, I'm trying to use a link from my own website for the HTML snippet (as mentioned above). For some reason I can get the map to show up on the published site when I pull the snippet from Dropbox, but not from my own site. The link to my own site works (if you open it in another window, you can see the map) and nothing else about the code has changed.
My public site is here, the HTML embed pulling the map is on the page called "Chapter 2" about halfway down. I currently have one embed pulling the snippet from dropbox, another one trying to pull it from my website.