After the Jaspersoft 7.8 upgrade, there is now an option to use a key during an export or import.
Which option should we select when promoting content (export / import) from a sandbox to production or other environment?
Only use the "Legacy Key" option for both importing and exporting.
The "Server Key" will not work. It is only meant for the same server.
It is not recommended to use the Server Key for export backups either even if on the same server,
Product Documentation on Jaspersoft 7.8 for Clarity