The value must be a code, not a description. "App Functionality" is App Store privacy-label wording; in PrivacyInfo.xcprivacy the NSPrivacyAccessedAPITypeReasons array takes the exact reason codes from Apple's table for that API category - for NSPrivacyAccessedAPICategoryUserDefaults the only valid one is CA92.1, and NSPrivacyAccessedAPICategoryFileTimestamp has its own set (C617.1 for timestamps of files inside your app's container, among others). Also worth knowing, because it turns a one-line fix into weeks of confusion: a plausible but nonexistent code (say CA92.2) passes every local check - Xcode accepts it, archiving succeeds - and fails only at App Store submission verification with exactly this ITMS-91055. So copy the category-to-code pairs from the documentation table rather than picking what sounds right, then diff every entry of every PrivacyInfo.xcprivacy (app target and extensions) against that table. That same diff closes the ITMS-91053s in the mail: the UserDefaults and FileTimestamp APIs your code touches need NSPrivacyAccessedAPITypes entries carrying those same valid codes.