You've gotten the idea to use a crazy or custom font. Heck with it. You hired me to invent you a font. I based it on your actual cursive. You used it for your chapter titles.
The book printing service returned you a book filled with black boxes! Oh, why!?
You need to embed it as a transparent image. Most printers, I know Createspace does as do other individual places, know a few fonts. They will read any unknown font as foreign. Stick to Times New Roman and the basics. Do not play around with fonts installed on your Mac.
Do not use image fonts for cutesy book touches. Black box. This. Will. Happen. Or an error like this.