I contacted live support, and they side that it's one of the mirror sites. I think they forgot to update the list of mirror sites. There could be more.
Now, it's confirmed that it's a mirror site of them then we should not worry much about it. They should update the list of the mirror sites so others won't get confused about it.
When someone's credentials work on both sites then that's a confirm thing that it's their mirror site. I'm sure if @Cantsay try the credentials then they will work on both sites because that one is just a mirror of the official site as confirmed by you after contacting their support.