please read first the explanation of the rejection "Artefakte" in the Contributer user guide:
You have photographed with a smartphone (Samsung Galaxy S8) and in general such a device can't handle such high contrast ranges as prevailing in your pictures, technically not without image errors as e.g. a single lens reflex camera can. You should consider that.
In all your pictures you can already see a noise and artifacts despite the low resolution posted here, I mean.
These technical errors on the smartphone are exacerbated by excessive image processing, which has led to the rejection of the images.
On the internet you will find a lot of information and picture examples concerning the topic noise and artifacts in pictures.
Adding to what v.poth said:
Which is why when zooming in these defects begin to show:
and therefore rejected based on this!