什么是政策例外？我找不到关于Android的任何信息

当我的应用程序尝试使用BackupTransportService备份其数据时，我的堆栈跟踪中会出现此错误。我在网上找不到有关它的任何信息，因此无法找出备份失败的原因。有什么想法吗

11-13 19:53:44.481: D/PerformBackupTask(352): starting agent for backup of BackupRequest{pkg=com.NsouthProductions.gradetrackerpro}
11-13 19:53:44.501: I/BackupManagerService(352): got agent android.app.IBackupAgent$Stub$Proxy@441b7118
11-13 19:53:44.501: D/PerformBackupTask(352): invokeAgentForBackup on com.NsouthProductions.gradetrackerpro
11-13 19:53:44.511: V/BackupServiceBinder(30648): doBackup() invoked
11-13 19:53:44.511: D/GradeTracker.MyBackupAgent(30648): onBackup called
11-13 19:53:44.511: D/BackupHelperDispatcher(30648): handling existing helper 'GradeTracker.db' android.app.backup.FileBackupHelper@425a93e0
11-13 19:53:45.382: E/BackupTransportService(352): com.google.android.backup.BackupRequestGenerator$PolicyException: server error in app com.NsouthProductions.gradetrackerpro: code 7
11-13 19:53:45.382: E/BackupTransportService(352):  at com.google.android.backup.BackupRequestGenerator.parseResponse(BackupRequestGenerator.java:360)
11-13 19:53:45.382: E/BackupTransportService(352):  at com.google.android.backup.BackupTransportService.sendRequestLocked(BackupTransportService.java:849)
11-13 19:53:45.382: E/BackupTransportService(352):  at com.google.android.backup.BackupTransportService.access$600(BackupTransportService.java:78)
11-13 19:53:45.382: E/BackupTransportService(352):  at com.google.android.backup.BackupTransportService$1.finishBackup(BackupTransportService.java:444)
11-13 19:53:45.382: E/BackupTransportService(352):  at com.android.server.BackupManagerService$PerformBackupTask.operationComplete(BackupManagerService.java:2320)
11-13 19:53:45.382: E/BackupTransportService(352):  at com.android.server.BackupManagerService$BackupHandler.handleMessage(BackupManagerService.java:572)
11-13 19:53:45.552: I/PerformBackupTask(352): Backup pass finished.

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解决了！我的Android备份服务密钥显然是坏的。我的清单中的包名中有几个大写字母，所以我想我应该确保我的密钥是由一个大小写相同的包名生成的。因此，我再次注册，从清单中直接复制/粘贴我的包名，我得到了一个不同的密钥，现在似乎可以工作了

许多类似的问题都是如此，但还没有解决方案。