Hi Charles,
Looks like the behavior you encountered is a little different from what other's experienced in this thread. The issue reported here involves courses encountering the three loading dots, and then seeing the course freeze from that point.
If you are able to go through your course from start to end, with some brief loading screens in between slides, I believe that your course is working properly, but it's always a good thing to test things just to be sure.
If you're unsure if your course is functioning properly, would you be willing to share a copy of your project file here or in private by opening a support case so we can take a look? We'll delete it when we're done testing!