Master Have an unregistered site Login as admin Turn on debugging Navigate to Messaging > Notification settings in site administration Under Notification plugins press Settings on the Mobile row Press Request access key Confirm the debugging is shown on the page similar to: Unexpected response from the Airnotifier server: {"error": "Site not registered on moodle.net"}   line 145 of /message/output/airnotifier/classes/manager.php: call to debugging() line 67 of /message/output/airnotifier/requestaccesskey.php: call to message_airnotifier_manager->request_accesskey() Moodle 3.8 Login as admin Turn on debugging Navigate to Site administration -> Messaging -> Notification settings Under Notification plugins press Settings on the Mobile row Change the airnotifierurl to https://example.com Save changes Press Request access key Confirm the debugging is shown on the page similar to:   Unexpected response from the Airnotifier server: {"error": "Site not registered on moodle.net"} line 145 of /message/output/airnotifier/classes/manager.php: call to debugging() line 67 of /message/output/airnotifier/requestaccesskey.php: call to message_airnotifier_manager->request_accesskey()