Encryption keys are specific to Management Zones. This means that a file encrypted in one zone cannot be opened on a device registered in another zone because the two zones do not automatically share keys.
If you have multiple zones and want to enable devices in all zones to open encrypted files regardless of the zone in which they were encrypted, you can manually share encryption keys by exporting them from one zone and importing them into another. For instructions, see Section 30.0, Exporting Encryption Keys and Section 31.0, Importing Encryption Keys.