They admit the mistake was theirs and they take responsibility for it. They say sorry. They explain what they're going to do to fix the situation. They say they're going to learn from this and not have similar mistakes in the future. Pretty solid.
The only thing that is missing, in my view, is personalization. Tell me who you are, speaking for the organization. This humanizes the apology, and also gives a face to who it is saying they're going to improve. Ideally the CEO.
Still, I give it 8/10.