Why was my model taken down, I can't even edit it anymore

If the preview image is not appropriate, I can replace it with a suitable one, but why is it not allowed to change it again? When I try to replace the picture in the third step of editing, it just shows 404. This brutal approach makes it impossible for creators to make adjustments to republish.

This practice is very irritating and difficult to understand. Overly abusive reporting can only spell disaster. I really hope that the community will adopt a more reasonable approach.

the site was probably having a "hiccup". Have you tried again after some time has passed?

If there was only one preview image which got flagged and removed, it might have caused a bug. If you can't fix the model, I would delete it and reupload it with new preview images. It's a good practice to have multiple preview images in any case.