Hard rejected - I need a feedback guys.

I have seen some very simple illustrations in GraphicRiver and since I do some by hobbie, I decided to send it for approval. But the first two that I sent were rejected. Basically this was the feedback “and unfortunately we found it is not at the standard required to move forward”

I wonder if you guys can help me in what I could improve or if these illustrations are far from the standard Envato.

Thank you very much.

Resolution matters also…