Robocopy over Samba

router: AX1800
firmware: 4.5.16
router connection to the Internet: I have an ISP provided Frontier Arris NVG468MQ FiOS Router that the AX1800 travel router is connected to via Ethernet
DNS server: DNS 1 - DNS 2 -
IP addresses: DHCP

First post so, apologies if this is not the place for this post. I recently set up the NAS feature on my AX1800 and intend to use it to host media files over my local area network.

Previously, I have been using the Windows command Robocopy to mirror an internal SSD folder to an external HDD connected by USB. Now that I have the NAS, I'd like to use the same process to mirror the drives over the network. I'm testing with smaller files now but the folder I will be using once I have sorted everything out is currently about 300 GB and will grow steadily over time so I am using Robocopy because it will check everything first and only copy the new stuff instead of copying everything.

After configuring the Network Attached Storage option to use SAMBA in the GLi.iNet web UI, I mapped the shared folder to my PC as the S:\ Drive using the Net Use command in the Command Prompt. After logging in with the username and password I specified in the GLi.iNet web UI, I can manually copy files to and from the NAS in this configuration. I then tried using Robocopy with the updated path.
robocopy "D:\Videos\Internal SSD Drive Mini Television" "S:\Mini TV" /r:3 /w:2 /MIR /e /SEC

This failed. This was the error messages received:
ERROR 1307 (0x0000051B) Copying NTFS Security to Destination Directory
This security ID may not be assigned as the owner of this object.

This seems to some type of permissions issue with the shared folder. This error seems to indicate that the username I created through the router web portal isn't the owner of the shared folder.
I can't find an option to change the User permissions on the router web portal and my attempts to change the user permissions or folder owner via Windows (Folder - Properties - Security Advanced - Editing Permission entries) results in an access denied message.

Any help or insight is appreciated.

Mostly Samba does not support the full set of access permissions NTFS handles.
So I would say you can't use /SEC in that case and might try /COPY:DAT instead.

Saving access permissions by this way isn't optimal anyway.
I would rather look into image-based backups, or at least creating archives before copying.

/COPY:DAT resulted in a different error message, so I will look into both image based backups and creating archives. Thank you for the suggestions. This is all new to me.

If you don't care about permissions you can simply omit /COPY:DAT.