Migration to FreeNAS Corral could be problematic for previous users because of mix-matched permissions.
If you imported Volumes and DataSet from lower version, and you end up not being able to access your new shears (smb), and you already checked its not a ‘net sh’ issue, then you should definitly try to open console/ssh and manually ‘chown’ those volumes because changing them via WebUI won’t resolve the issue.