NFS mount fails with mount.nfs: access denied by server when using AIX as NFS server

Issue

• mount.nfs: access denied by server when mounting NFS share provided by AIX.

• When trying to mount the a NFS share, the NFS client shows permission denied error:

  # mount -t nfs -vvvv 10.X.X.123:/nfs_server /share/ -o nfsvers=3
  mount.nfs: timeout set for Thu Jan 23 12:30:00 2019
  mount.nfs: trying text-based options 'nfsvers=3,addr=10.x.x.123'
  mount.nfs: prog 100003, trying vers=3, prot=6
  mount.nfs: trying 10.X.X.123 prog 100003 vers 3 prot TCP port 2049
  mount.nfs: prog 100005, trying vers=3, prot=17
  mount.nfs: trying 10.X.X.123 prog 100005 vers 3 prot UDP port 36793
  mount.nfs: mount(2): Permission denied  <--
  mount.nfs: access denied by server while mounting 10.X.X.123:/nfs_server