Help me understand why the following sentence is incorrect?

Question

Are you going out to buy bread this morning?  Can this also be translated as:  Va (usted) a salir a comprar pan esta mañana?  If not why not?I don't understand why instead you'd use:  Usted sale a comprar pan esta mañana?Thanks, Lia

Answer

Hola Lia
Your sentence is also correct. They reason why it's marked wrong is because the hint is saying to conjugate salir in the "present" and you're using the "near future" (voy a..., vas a..., va a... ). But I can see why it's confusing. The natural English translation is using the near future. In Spanish, the present sometimes is used with a future nuance. To avoid confusion I changed the sentence to:
Do you go out to buy bread every morning? 
This way, the present is the only option.
I hope it helps.
Saludos
Inma