Originally Posted by rstoothoff
I'm asking both questions, but in particular why the Calibre-generated .mobi/Kindle file is unacceptable. How does it differ from a Kindlegen-generated file? it looks good in the Kindle app and Kindle Previewer, in fact better than the Kindlegen-generated files.
The point is that neither question is a calibre forum question.
The reason Amazon is not accepting calibre generated ebooks is a question only Amazon can answer. It is their prerogative to handle their business the way they see fit. Anything we say is speculation.
Your question about kindlegen and why the output isn't to your liking should be asked in another forum, perhaps if the question was asked in the Kindle
forums it would be both on-topic and have the expertise reading those forums to answer your question.
Obviously for personal use calibre is still #1.