What reason did Adobe give for rejecting it -- technical, intellectual property, improper file type, etc...?
Offhand, I can only say it's too small and too dark. Open your native file and examine it at 200-300% magnification. That's when you notice the imperfections that require attention.
If you'd like for us to give you accurate feedback on your file you must have a size that we can zoom in on. We cannot provide you with feedback on a thumbnail. The only thing I can see with this thumbnail is that it is underexposed. There might be other issue that we cannot see. Here is an example of file size we can work with:
@christinemcnamara The image file you shared here is far too small for us to examine. We don't have access to your account or anything like that to know the reason your image was rejected. Please give us a much larger file and the reason given and we'll see what we can determine.