why is az alma esik az uj iroasztalra wrong?
It should be accepted. Report it, please.
It is not wrong but note that you are emphasizing the apple. The apple, not some other fruit, falls onto the desk.
Az alma ráesik az új íróasztalra. This is a better translation of the sentence. However, Duo do not like it.
Why not esik le, or leesik? Unlike the frog already sitting down, this apple is actually in the act of falling, in motion, so?