You can try to set smb protocol version to smb2 or smb3 on your nethserver.
create a new template with the editor you like, I use nano:
nano /etc/e-smith/templates-custom/etc/samba/smb.conf/20smbversion
and write
protocol = SMB3
or
protocol = SMB2
at this file. Try which one works for you. After creating the file with the protocol-version you have to expand the template with
expand-template /etc/samba/smb.conf
For more details about working with templates have a look at the documentation:
https://docs.nethserver.org/projects/nethserver-devel/en/v7/templates.html
At the following link you can find some information about the tip with the protocol