iPhone push notifications stop: DeviceTokenNotForTopic

We are facing an issue: push notifications are not being received. We are using the Marketing Cloud SDK for push notifications.

On install, the app correctly registers for push notifications. We pass the required information to Marketing Cloud — for example, contact key, token, etc. Marketing Cloud also confirms that the configuration is set up, and we have tried sending push notifications with proper delivery settings.

The issue is that after some time, the device gets automatically opted out in the Marketing Cloud portal. When we consulted their team, they said this is caused by the “DeviceTokenNotForTopic” error received from APNs. I have verified the certificates and bundle ID from my end — everything looks correct.

Device: iPhone 15, iPhone 17

iOS: 18.7.2, 26.1