I like the wreath in yours better, but overall your photo is not as pleasantly composed as the one that is there. Yours is a bit too tight to the subject. There's no room around it for anything.
Speaking of composition and angles, you can see the white/blue building behind the main building (on the right) better in the Stock image as well. In yours it's a distraction because it's just kind of peeking out a bit so there's nothing to resolve what it is in a viewer's mind.
Also, the water is higher in the Stock image and it looks nicer because of it.
Now, if there were no shots of this already in the Adobe Stock collection, maybe this one would have been accepted. I don't know. But when there are more useful and more pleasing images of the same thing from nearly the same angle with nearly the same lighting...why add an inferior image? I don't work for Adobe so I don't know for sure about their reasoning, but I do know that if it were me and I already had the other one in my collection, I would reject yours too.
Appreciate the feedback
Your'e welcome. It's too bad the other photos got there first! You've got a nice photo of what looks to be a beautiful place!