The Augsburg Confession did come from an Ecumenical Council, it was a Lutheran document, and it was not acceptable to the Roman Catholic Church. It may sound like a Catholic creed but is not for two reasons:

First, Luther did not really know what St. Paul meant by "faith", or justification, for that matter, yet he built his whole system on his erroneous opinion. Second, Luther held there was no teaching authority outside of one's own reading of scripture.