Google recently changed something about their Sheets service which is causing many people to run into an error when they are making a new timeline.
Note: there should be no impact on existing timelines!
After this change, many of you click on the "preview" and get this message:
An unexpected error occurred trying to read your spreadsheet data [SyntaxError]
Timeline configuration has no events.
There is a straightforward work-around, but it requires those of you who have been making timelines for a while to change your habits.
It used to be the case that the URL in the Publish to the Web window was usable for "step 3" of the publishing process. As of today, that URL is different from the main spreadsheet URL, and if you use the URL from the Publish to the Web window, you'll get the error above.
Instead, disregard that URL, and instead, use the URL from your browser's address bar:
We're sorry for the inconvenience. Unfortunately, sometimes Google changes things on us.