CIFS/SMB share access does not work anymore on my Tumbleweed system

i have a NAS server PC running freeNAS i use as storage device. The system is configured to provide access to the storage via a bunch of different network shares. For linux only stuff i use some NFS shares and for some stuff needed on my Windows system (Windows 7 dual boot and Windows 7 running on VirtualBox) as well, i have a cifs/SMB share.

Last week i did a kind of larger upgrade of the freeNAS os running on the NAS and since then i cannot access the cifs share with my linux system anymore! But i still can access the share from Windows (dual boot and VirtualBox as well), the NFS shares also work.

So to make this clear, only Tumbleweed access is broken, i still can access the share from windows.
This is the command i used before, which worked since the beginning:

sudo mount -t cifs // /home/sabo/NAS_Public -o username=sabo,uid=1000,gid=100

And this is the error message i get when running the command (and applying the correct passwords):

[sudo] Passwort für root: 
Password for sabo@//  ***************
mount error(95): Operation not supported
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)

So, since access from windows still works, the problem could also be related to tumbleweed, maybe some recent update broke the functionality?

Kernel 4.13 changed SMB defaults. Please have a look at: