SL 360 Accessibility: Screen reader reads page name, but then says "blank." Can a page description be added? How?

I'm creating a template SL360 course for "best practices" in accessibility. The screen reader (NVDA) reads the screen name (for example, Introduction to Widgets) but then says "blank." Seems like it is looking for additional information (maybe a description of what is on the screen), but I can't find where that information could be included. What am I missing?