I tried to load about 20 pictures and after 5 days they were rejected due to techical issues. What are they exactly in these pictures?
You have problem with exposure, they are a little underexposed. Look at your histogram. There are also problems with focus, they are not sharp, but this is due more to depth of field - it is very shallow. You don't have any point of focus - meaning where/what can the eye focus on? Eg, The bee isn't sharp:
The composition is not that good. I also think there is a problem with the white balance.
This is from Adobe's help files: