I noticed that system backup does not work at all.
I have just reset mikrotik hap ac to default configuration and when I try to make backup and restore it I see the following error (the same error):
[admin@MikroTik] > /system backup save name=mybackup
Saving system configuration
Configuration backup saved
[admin@MikroTik] > /system backup load name=mybackup.backup
password: *****
Restore and reboot? [y/N]:
y
Restoring system configuration
Failed to restore system configuration
action failed (6)
That password is a backups password, not a user password. You did not specify any password on backup save, so you should leave it empty on backup load as well.