System Restore isn't working for me- HELP!

[RainCaster]

I backed up my whole system to an 8TB external (USB3) drive formatted with ext4. The backup was done as "External Backup". After a long time, it finished. I then did a System Settings -> Export Settings. Then I reformatted the volume for btrfs (previously ext4). After a very long time, it finished and I tried to do a "Systems Settings -> Import Settings. The response was "Unable to import system settings (Ref. 5401)". What does that mean? How can I fix it?
Also, I am unable to restore the Volume from the backup I made- how does that work? I cannot find a way to do that.
The NAS is a AS6208T modified to take 16GB of RAM, using ADM 3.5.5.RFC3. The bays are filled with a mix of 5 & 8 TB drives.

[orion]

mm... I did not try to restore system settings after changed file system. No comments about it. I think you'd better to send a support ticket to asustor to know what the error code is.

Regarding to volume restoration, what's the error? You should post details here.