Why was this AI-generated image not accepted? [ALL CAPS removed by moderator]

There are some small (by physical size) issues with your asset. I've marked some of them, not all:

Generally speaking: the buyer does not wish to spend hours of correcting the asset. That is your task.

Hieroglyphic symbols and gibberish screen text has no commercial value to potential customers. 

That's why it was rejected.

If you want to deep dive into AI, remember that machine-generated content isn't art.  It's a tool to help you create your own artwork. 

Some AI mistakes can be fixed, others can't.  You must decide if it's worth the effort or not, and have the desire & talent to make AI into commercial quality artwork.  It's OK if you don't.  AI isn't for everyone.

Stock also accepts photography, manually created 2D & 3D artwork as well as videos.

Hope that helps.  Good luck.

The finer details aren't legible. Quality goes beyond file size. AI has a hard time with the details required for something like the keys on a laptop or small text.