On my Lubuntu 16.04 I connected to my NAS and was not able to delete files. The error message was something like:
Deletion log file could not be created: No authorization.
My connection to the share is established through:
sudo mount -t cifs -o user=USERSERVER,uid=LOCALUSER,gid=LOCALGROUP,username=USERSERVER,password=PW //192.168.0.102/RAID6 /media/OMV