Problems formating Pages to create PDF for KDP

I'm experiencing trouble getting the trim size accepted by the KDP onboarding software. I've followed formatting instructions rigorously, save for dialogue, for which I am using an indented em-dash I've set up by adjusting the margin. I'm writing novels, and text is exceeding the trim size by a long shot. KDP's native scaling operation results in downsizing everything too far and giving tiny paragraphs within oversized margins.

I've had a book's content uploaded once successfully, but never again since. Ideas? Thanks, LJG