Can't generate a label preview

I've created a new label layout and template and tested it with a set of records, and it's working correctly. When I try to Generate a Preview it just generates a blank page.
I also made sure I had a found set for it to work with, but the Generate Preview feature still created a blank preview.
What am I missing?
I also made sure I had a found set for it to work with, but the Generate Preview feature still created a blank preview.
What am I missing?