ACFS-05913: unable to contact the standby node stbyrac1

Problem:

I was trying to setup ACFS replication, where one of the steps is to validate keys using acfsutil, which failed with ACFS-05913 error:

[root@rac1 .ssh]# acfsutil repl info -c -u oggrepl stbyrac1 stbyrac2 /GG
acfsutil repl info: ACFS-05913: unable to contact the standby node stbyrac1
acfsutil repl info: ACFS-05913: unable to contact the standby node stbyrac2

Cause: 

An attempt to use the ping utility to contact a standby node failed.

Solution:

Enable ICMP traffic between these nodes and retry validation:

[root@rac1 .ssh]# acfsutil repl info -c -u oggrepl stbyrac1 stbyrac2 /GG
A valid 'ssh' connection was detected for standby node stbyrac1 as user oggrepl.
A valid 'ssh' connection was detected for standby node stbyrac2 as user oggrepl.