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?

Hi. There seems to be some fragility to the preview creation for newly created templates. I'm not sure what causes this as it is kind of infrequent. What I do is copy (take a screen shot) of a preview from a mail merge using the template (from the "Preview" of my merged data) and paste that in to the template preview in Settings. It' a bit manual but you only have to do it once per template.

Hope that helps.