Good tip. I was stuck on same issue and this fixed it. When attempting to provision new datastore using VSC 5.0 from VCenter via VSphere web client I was getting these errors:
NFS mount <lif IP>:/<new_vol_name> failed: Unable to connect to NFS server.
Sysinfo set operation VSI_MODULE_NODE_mount failed with error status Unable to connect to NFS server.
The attempts were creating an export policy and populating it with the IPs of my ESXi hosts.
To fix I opened Netapp OC System Manager and went to:
Storage Virtual Machines - VServer (name) - Configuration - Protocols - NFS
and enabled NFS there.