I've had a daily backup that has been working properly for several years and many upgrades.
After the latest upgrade from 6.15 to 7.2.1, they have started to fail with:
2020-02-04 13:42:52,980 WARN [Caesium-1-2] [activeobjects.confluence.backup.LoggingBackupProgressMonitor] beginBackup Begin Active objects backup, change log level to INFO for com.atlassian.activeobjects.confluence.backup for more detailed logging.
2020-02-04 13:42:54,670 WARN [Caesium-1-2] [activeobjects.confluence.backup.LoggingBackupProgressMonitor] endBackup Completed active objects backup.
2020-02-04 13:43:01,784 ERROR [Caesium-1-2] [confluence.importexport.impl.BackupJob] runJob Error while running the scheduled backup
java.io.IOException: Permission denied
at java.io.UnixFileSystem.createFileExclusively(Native Method)
at java.io.File.createNewFile(File.java:1012)
at com.atlassian.core.util.FileUtils.copyFile(FileUtils.java:407)
at com.atlassian.confluence.importexport.impl.BackupJob.runJob(BackupJob.java:68)
I've tried changing the log level to INFO for com.atlassian.activeobjects.confluence.backup for more detailed logging (And even TRACE), but it doesn't give me any information on what file it's attempting to create and fail on.