Before troubleshooting, first thing I want to ask :
Is the export-policy enabled? (By-default it is disabled for cifs)
According to the KB below: Since 8.2, export policies have no effect on CIFS, and only CIFS ACLs and share level permissions determine access. If you want ipbased (export policy based) access restrictions for cifs to apply, modify the corresponding advanced level cifs vserver option with cifs option modify on the cluster.