Permissions on document subfolders

Hello.
Some time ago I ran into errors on my backups of the Dolibarr documents (invoices, etc). After looking into it, I saw that the new subfolder, that is created with every invoice for example, has different permissions than the others. When I look at permissions I see that “Others” have “no list, no create/delete, …” permission set and so the backup has no access and so does not backup my files.
Could someone please tell me what permissions I need to set for the documents folder and how I can ensure that the newly created subfolders, that are being created by Dolibarr, will permit a backup?

Thank you in advance!

B