I have tried both ""Piros madarak énekelnek a magas fákon" and "Piros madarak a magas fákon énekelnek" and both were rejected.
Why are not both of these acceptable?
I have had the same problem. I understand Hungarian is supposed to have a more flexible word order, but I don't really see it.
they probably just overlooked it. Your sentence would emphasize that it is the red birds that are singing, not that they are in the trees.