it's also right ! I think this depends on the context http://deutschinallerwelt2.blogspot.com.au/2014/02/136-word-order-in-main-clause-ii.html
If there is any confusion as to which noun/pronoun is nominative and which is accusative then the nominative should come first. Here Alle and sie can both be plural and are the same in nominative as accusative, so the grammar endings provide no clue. There is no other context to suggest that sie is the nominative so we must go with the word order: Alle as nominative and sie as accusative.
At this language level I think this should always be the case, it gets too confusing otherwise. It's true that DL has a couple of examples with the plural accusative before the plural nominative ("Hausgeräte haben meine Eltern" of similar) but I think that is a poor sentence at this level because although meine Eltern would be much more common as the nominative, without clarifying sentences either side of it you can come up with examples where the appliances "have" the parents.
So the accusative form of "sie" is "sie"?
(And this causes Germans learning English similar problems to English speakers - for whom the objective form of "you" is "you" - learning German. They will say things such as "I like she" or "Do you know they?".)