That actually is canon. It's why no one is responding to Leia's distress call.
The problem is that it is not shown or stated in the movies themselves. And sadly there's a title crawl. They could have added just a sentence or two to it and boom it is covered!
After the Force Awakens came out, there was a stage act put on at Disney World. A few First Order Troopers came out, did a photo opt with a kid dressed as Kylo Ren. While posing, one of the Troopers said, "There is no Order without the First Order."
I'd like to think that's a Canon propaganda slogan used by the First Order.