When the following error appears "communications error occurred while attempting XMLRPC sync with username admin@<Soure IP> @<time stamp>"

This error is due to the HA (High Availability) between the firewalls.

Definition of HA (High Availability) 

High availability (HA) is a deployment in which two firewalls are placed in a group and their configuration is synchronized to prevent a single point of failure on your network. A heartbeat connection between the firewall peers ensures seamless failover in the event that a peer goes down.

The following items need to be checked to ensure proper XMLRPC configuration synchronization between two firewalls:

  1. The Username must be admin on both firewalls.
  2. The Password must match on both firewalls.
  3. The webConfigurator must be on the same protocol on each cluster node (HTTP vs. HTTPS).
  4. The webConfigurator must be on the same port on each cluster node (e.g. 443).
  5. The Sync interface on the secondary firewall must be enabled.
  6. The interfaces on all nodes must be assigned in the same order.
  7. The Synchronize Config to IP option on the primary firewall, must point to the sync interface IP address of the secondary firewall.
  8. Traffic must be permitted to the webConfigurator port on sync interface of the secondary firewall.
  9. Verify that ONLY the primary firewall has the various XMLRPC config sync options checked.
  10. Remove any IP address in the XMLRPC Sync section of the config on the secondary firewall.