My girls won’t go inside!

I’ve had my chickens for about 3 weeks, and about a week ago the girls started to not go inside their coop at night. They have preferred the roof of their coop instead. I have an automatic door set up to close at 9:20pm. It’s pitch black by that time of day. I’ve tried completely deep cleaning their coop and replacing bedding and added a wider roost bar inside the coop, so I’m not sure what else to try! Any advice?