What reason did Adobe give you for the rejection? Technical issues?
The white balance is off (the photo is too pink.) There is a lot of noise in the photo, especially chromatic (colour) noise. The thatch umbrella could benefit from a little sharpening.
On a side note, it looks like a lovely place to be right now. 🙂
I would guess that this is correctable, especially if you have access to the raw files. If you correct, you could also correct the slight level error of the horizon. I do not think, however, that this was a reason to refuse the image. A small texture/clarity push will help the roof of that sunshade.
The sky, when viewed at >200%, has some wierd compression artifacts.