"Are you listening?"
Translation:¿Tú estás escuchando?
I was careless the first time I had this question and got it wrong. This was the tip I was then given: Here's a tip "When talking about the present, you should use the form escucha with él / ella / usted!" What does that have to do with this question? (Since you can't comment on Tips I'm posting this here.)
You did not tell us what your answer was, so it is not quite clear what the issue was.
The English sentence has "you", and that pronoun is ambiguous. It can be singular or plural, and in Spanish, familiar or formal. Therefore it can be translated as tú, usted, vos, vosotros, vosotras, or ustedes. All are correct, and Duolingo routinely accepts all possible forms that work in the sentence. However, you must match the verb to the pronoun.
So possibly you opted for usted, which is fine, but you might have used the wrong form of the verb. Just guessing. So Duo was telling you that ¿Usted escucha? would be correct.
And that raises the question of the verb, which can be simple present, as in your answer, or in the continuous, in which case the answer would be ¿Usted está escuchando? The continuous is used for actions happening at the very moment, and is maybe better here.
And this is a lot to say about a sentence that is just three words long! No offense, though.
In this case Spanish asks questions typically by inflection of tone rather than swapping words around like English and German. I’ll break this down for you: Tú - informal second person Estás - conjugated verb estar Escuchando- a second verb (escuchar, to listen) in the continuous present.
This is a bit more complicated, but Spanish doesn’t normally say things like “(Tu) estás escuchando” unless the person is doing it at that exact moment. Most people would probably use “(tu) escuchas?”. Spanish doesn’t have the “do” helping verb like English so most of the time it’s just subject and verb. It sounds a bit weird to English speakers since we use the “do” and the present continuous constantly.