Lost access to SMB share "Permission Denied"

Hi, I am relatively new to Freenas (11.3) and currently having some difficulties accessing a windows share. Initially I had setup a SMB share and was able to connect to it via my Ubuntu client. Also successfully tested connection from a windows 7 machine. After copying my data across to the share I decided to create individual user accounts under one group that had access to the SMB share.....and that's when all my difficulties began.

Current dataset in question is "Mediaset":
[ATTACH...

Lost access to SMB share "Permission Denied"