Why is avez-vous not correct if as-tu is?
It should be accepted but has been missed. Report it so it can be added to the list of acceptable responses.
It didn't accept it when I just tried it.
What about < ce matin-ci > instead of < ce matin > ?
"-ci" is not necessary and even redundant.
Why does not "Est-ce que tu as reçu le journal ce matin" work?
This should be accepted. Please report it to have it added to the list of accepted translations.
They must have fixed it because I gave this as an answer today and it was accepted.