Reasons for the Rejection

When creating AI images you ned to think, "who would pay to download it?"  In this case there are already over half a million images of a piece of real chocolate cake in the stock library so new AI ones need to be of the very best quality to be of any interest..

I can't repeat it enough: avoid the default 1:1 aspect ratio of AI. Give the buyer some room to add copy or to crop as the buyer feels necessary.