It's the border around your photo. Remove it and resubmit.
Read these links:
The border is the immediate problem; however I think it's also a bit soft. Could you some sharpening and contrast improvement.
The depth of field and focus is not good and the right edge is too close.
Pienso lo mismo, tambien reencuadraria esta demasiado a la derecha, pondria el motivo mas al centro