Make sure your child hasn’t changed the password for their Apple ID.  In addition, check to make sure they’ve not removed the BrightCanary server from the list of devices with access to their Apple ID information. This list is found by opening Settings on their device, then tapping iCloud (their name) at the top of the screen. Scroll down, and you should see a list of devices with access to their Apple ID, including their iPhone and/or iPad, as well as a BrightCanary server. If you do not see a BrightCanary server in the list, email support@brightcanary.io for help getting things set up again.