RHEV fencing fails with message 'Failed to run Power Management command on Host <host>, no running proxy Host was found'

Issue

Red Hat Enterprise Virtualisation (RHEV) iLO 4 host fencing fails when the network service is stopped on one of the clustered hosts. An attempt to find a host to perform the actual power off is made and then retried. During each attempt, the following message is seen in /var/log/rhevm/rhevm.log:

INFO Attempt 1 to find fence proxy host failed...
INFO Attempt 2 to find fence proxy host failed...
INFO Attempt 3 to find fence proxy host failed...

These attempts to find a host to perform the actual power off time-out and the following error is then issued in the same log:

ERROR Failed to run Power Management command on Host <host>, no running proxy Host was found.