Why is my book preview still loading?

Select Preview to open the preview. If the button is greyed out, your book is still being calculated — wait for the page count to settle and it becomes available.

The preview is not built in one go. It is produced in batches, so the first chapters become readable while the later ones are still being made; a chapter with a spinner beside it is not ready yet. A long book takes a few minutes to finish, and then you can read the whole book, cover to cover.

If it does not progress at all, close the preview, wait a minute and open it again: the pages carry on being built in the background. If it still will not build, reload the page.