Some clubs using Nettla has set up a connection to manage automated light and access for their facility. The court lighting system is often based on a timer 'before' and 'after' your sessions start time, meaning that lights can turn on 5 minutes before to 5 minutes after (or whatever number the club has decided).
If your court lights are not working for any reason, please reach out to the club directly and ask what their rules are and mention that the lights are off. They will either be able to help you with a manual-turn-on or check if there is something that is not right regarding the automated connection.