I'm now on the process of developing a Mobilepush app SDK and still on the step of testing, there's a issue regarding Opt-out method. We keep failing to receive a push message because the system automatically opts out even though we basically did not try 'opt out' in the app. It keeps give us 'Service feedback' fail message, but we don't know what exactly went wrong in this case. As far as I know, APNs system provides at least one feedback a day, but when it fails to meet the feedback,it handles it by 'Service feedback' error.The error generally happens when users try to delete app or literally try to opt out, but it isn't the case. Can anyone share the case why, or when this error happened? It would be okay if it's not a first hand account, anyting would be a huge help.