Duplicati to Backup Truenas


I am trying to use Duplicati to backup my TrueNAS (aka FreenNAS) out .
I post on TrueNAS forum , but posting ere to see if someone here might have the solution

I am trying to use Duplicati in a Jail for the backup task out in the cloud.
everything seems great , except some permission issue on some file.
Duplicati process do not seems to have access to backup those files (most of the files are 700 permissions with a user not define in the Duplicati jail)

Anyone was able to setup this or able to help get around this issue?

thanks in advance.