Possible reasons for rejection?

I would say: Quality issues, and that is probably what Adobe did tell you.

There is an exposure issue, as you can see on the histogram:

If you dig a little deeper, you see artefacts that cause this "nice" high contrast look, but that basically destroyed the underlying picture by this processing: 

You have the same unnatural situation everywhere in your picture. Such a processing brings a lot of likes in social media, but makes the images unfit for Adobe stock. 

The photo is over sharpened.

A possible reason for rejection is your composition. The foreground interferes with the background. Don't have the trees. They blend into the rocks in the background!

Composition:
https://www.adobe.com/creativecloud/photography/discover/photo-composition.html

Unrealistic, perhaps over-processed detail. Did you apply some sort of filter to this image?