From the APNS documentation, - https://developer.apple.com/documentation/usernotifications/setting_up_a_remote_notification_server/handling_notification_responses_from_apns an error with error coded 410 will be thrown if a push token is no longer valid. However, Our company is seeing cases where stale push tokens (i.e. tokens that haven’t received any notifications in over 1 year) aren’t getting a 410 error back from APNS. Will APNS throw a 410 error for stale push tokens? What are the conditions under which a 410 error code will be returned?

For users who initially deny push notification permission, we want to re-engage at a later suitable time and suggest them to enable push notification for our app. We wanted to check if Apple has any restrictions on the number of times "Allow Push Notification" pop-up can be shown to the user.