Was having a weird epub issue, where an epub I'd made was fully readable on PC but on any other device it stopped about twenty pages in. Anyway, turned out it was an HTML thing: I'd edited it in HTML and left a couple of empty <p></p> tags by accident. Once I fixed that, it worked fine! Just putting this here in case anyone else has had the same issue.
@frankpodmore Huh, I'd have thought a couple of empty <p></p> tags shouldn't break things.
@frankpodmore Could be! Still kinda silly though, because HTML is supposed to be extremely forgiving. Forgot to close it? No worries, we'll just ignore it now! Guess the rendering engines of the other devices were a bit too strict and ignore means 'do not display'. ;)