Yes, I have tried rebooting the phone. That hasn't work either.

We already call registerForRemoteNotifications() on every app launch. Which does successfully catch when the device token changes and updates it on our server. It has successfully worked before as well as for other users. In this user's case the device token has not been updated since the last time their notifications were working.

We do call registerForRemoteNotifications() at every app launch. It does successfully catch when the device token has changed and updates it on our server. It successfully works with other users and with this user in the past. But currently in this case the user's device token has not changed since they were last receiving notifications via NSE.