"Your question does not have an answer."
Translation:Η ερώτησή σου δεν έχει απάντηση.
Η ερώτησή σας δεν έχει απάντηση is rejected with : Η ερώτησή σας δεν έχει κάποια απάντηση as the correct answer. Anybody can explain please?
When a word is stressed on the third-to-last syllable and is followed by a possessive pronoun, the last syllable gets accented as well. In fact, in my understanding, the course is wrong in saying that both forms are correct; the double-accented form is the only correct one.