You are correct and I finally figured out how to fix it. Instructions on Google were not complete/clear so I had to search for ti and found answer on independent sources. It would be a great help to your customers to include instructions here on the Calendar’s website since without it your calendar is not functioning. Here is where I found the answer http://ansonalex.com/tutorials/google-calendar-public-events-are-no-longer-visible/
Additionally I do have one concern about taking 2 days to reply to my question – from a paid customer – I expected better.