The translation given at the top of the discussion is the same as the one that you wrote, so it's very odd that your answer was not accepted. Are you positive that the sentence you wrote here is exactly the same as the sentence you wrote in the exercise? For example, if you accidentally left out "a," your translation probably would have been rejected. If you get this one again, and "I am not a machine" is rejected again, use the Report button. Maybe it's a bug.