Mounting Drobo5N in Linux

So I am trying to mount my Drobo on Ubuntu OS

Made the directory

sudo mkdir -p /mnt/shares/Drobo5n

when I mount with following command and check the mount with df -h I can see the mount

sudo mount -t cifs // /mnt/shares/Drobo5n

this is what my fstab looks likes

// /mnt/shares/Drobo5n cifs user=sunny,pass=sunshine,iocharset=utf8,vers=1.0,dsec=ntlm 0 0

when I do mount -a

I get an error

mount error(22): Invalid argument

Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)

Any help would be greatly appreciated.