Why this error occuring "mount.nfs: portmap query failed: RPC: Remote system error - Connection timed out" while mounting NFS share?

Issue

• Attempting to mount a NFSv3 share, results in the following:

  mount.nfs: prog 100005, trying vers=3, prot=6
  mount.nfs: trying xx.xx.xx.xx prog 100005 vers 3 prot TCP port 1017
  mount.nfs: portmap query failed: RPC: Remote system error - Connection timed out   <---
  mount.nfs: trying text-based options 'vers=3,addr=xx.xx.xx.xx'
  mount.nfs: prog 100003, trying vers=3, prot=6
  mount.nfs: trying xx.xx.xx.xx prog 100003 vers 3 prot TCP port 2049
  mount.nfs: prog 100005, trying vers=3, prot=17
  mount.nfs: portmap query retrying: RPC: Timed out    <---