I'm not sure why this was declined but I guess it's because of the plane there in the sky (non-nature elements shouldn't be visible, see the rules for further information: [link]) Talking about the plane, I think it would look better without it, it's rather a distracting element and it shouldn't be a big problem to get rid of it with the clone tool. The composition is very good already but I think it might look a bit more balanced if you'd show more of the bottom part. Have a look at the rule of thirds: [link] Another last thing, I think the vignetting is a bit too strong. The vignetting effect itself isn't bad though.
The dreamy mood, the soft colours and the layers are wonderful, you did a great job here, keep up