"The author does not say the color."
Translation:El autor no dice el color.
Write this in Spanish: "The author does not say the color." Didn't accept "La autora no dice el color," and gave "El autor no dice el color" as correct answer. Confirmed on Spanishdict that there is a feminine form (la autora), and thus reported this as an answer that should have been accepted.
All objects of unknown genre are assumed masculine, not just in Dpanish but in most languages as well. Its, therefore, much more natural to use the masxuline form, although the feminine is also contextually correct.