NextcloudPI - Restore-Problems with NAS

Hello,
could somebody tell me why a backup to a mounted NAS-directory doesn’t work?
I mounted the directory of a Synology-NAS to a RaspberryPI under NextcloudPI in the normal way.
The backup worked, but while restoring there was an output to screen like
nextcloud-13.0.0.14/3rdparty:

Kann Datei-Eigentümer nicht zu uid 33, gid 33 ändern: Keine Berechtigung
that means a violation of rights. Nothing was restored.

My question: is such a process a possible way and how can I overcome this problems? The method of syncing the data-folder to an external folder is inpractical as it syncs only the data-directory and not the database.
Thanks in advance!

goestr

Hello,
I found some typos in my post.
So here is the corrected one:

Could somebody tell me why a Nextcloudpi-backup to a mounted NAS-directory doesn’t work?
I mounted the directory of a Synology-NAS to a RaspberryPI under NextcloudPI in the normal way.
The backup worked, but while restoring there was an output to screen like:

Kann Datei-Eigentümer nicht zu uid 33, gid 33 ändern: Keine Berechtigung

That means a violation of rights. Nothing was restored.
My question: is such a process a possible way and how can I overcome this problems? The method of syncing the data-folder to an external folder is inpractical as it syncs only the data-directory and not the database.
Thanks in advance!

goestr