I was getting this error while accessing a NFS share on FreeNAS from my linux Desktop.
i was using the below command which was inncorect
#mount -t nfs -o username=root,password=xxxxx //10.0.10.8/mnt/volume-1/Linux-free-Sharing /home/vishal/nfs
The error resolve using the below command
# mount -t nfs 10.0.10.8:/mnt/Volume-1/ /home/vishal/nfs/
10.0.10.8 is My FreeNas Storage Server
/mnt/Volume-1/Linux-free-Sharing is the share which i configured on FreeNas Storage Server
/home/vishal/nfs is the directory which i created on my Linux Desktop for mounting the FreeNAS Share