Could you help me solve my question, about why my photo was rejected? I do not understand!

Zoom in on the duck's eye and you'll see that it is not in sharp focus. Also, as mentioned by Ralph, blown out highlights, underexposed shadows and chromatic aberration.

The duck needs sharpening and parts of the white are blown out (overexposed) and if you look at 250%, you will se a purple halo around the duck.

Adobe told you a basic reason. What is the reason? Perhaps we can add more detailed ideas, but don't make us guess!