Mobile notifications No registered devices

Hello

I use Moodle Mobile 2.5 and Moodle 2.9.3+

I had a set according to docs(https://docs.moodle.org/29/en/index.php?title=Mobile_app_notifications, and so on) in order to enable push notification.

However, push notification is not enabled.

I connect Moodle Mobile app in order to register my iPhone and iPad with the Moodle site.

But, check Preferences>User account>Messaging "Mobile notifications" field

display a message "No registered devices. Devices will automatically appear after you install the Moodle Mobile app and add this site."

DB user_devices table register my devices. But, DB message_airnotifier_devices table is empty.

Thank you to anyone that can help. Forgive my bad English.