"He did not answer my question."
Translation:Li ne respondis mian demandon.
Allowed, yes, but developers have to add all accepted translations manually, and so they cannot really add all grammatically possible permutations of words.
In general, stick to adjective-noun and SVO word order on Duolingo. When writing poetry or talking freely, you can be a bit freer but here on Duolingo, have compassion on the course maintainers....