copy to NAS creates a "strange" ._filename

[Ammammata]

hello there

I never noticed this, it's the first time I use TC on this computer to copy a file from the local hard disk to the NAS

https://i.imgur.com/s3Qo1Ly.png

Files on the left are local, in folder Links; files on the right are on the NAS, in the parent folder (you can see Links at the top)

When I try to copy this file (Image 1867.tif) to the same Links folder on the NAS I get the error "Please remove the write protection" and below (translated into English) "Request execution impossible due to an I/O device error"
If I copy any other file it works
If I copy the a.m. file to the parent folder (see picture) it works and automatically creates this "._Image 1867.tif" file that's NOT a tif file but something different, it has a "netatalk" word in the header (when I use the viewer), something related to Apple?

any idea about this?

Thank you in advance

[Ammammata]

Half answer to my post, about the ._ file, maybe it's this: https://www.bleepingcomputer.com/news/security/qnap-warns-users-to-disable-afp-until-it-fixes-critical-bugs/
I disabled the option in the QNAP (not needed, noone accesses the disk using a Mac), it will reboot this night

[Dalai]

Do you get the same result when copying the file(s) with Explorer? My guess is that this is the NAS software doing its thing (whatever that is).

Regards
Dalai