Problem if the agent on target system is not running or unreachable:

If you receive an error similar to the one displayed in the screenshot below, verify that the host specified in the IP address field is correct and that access is not blocked by a firewall or security group. If the problem persists, connect to your instance via SSH, become the root user and restart the Charon Agent (# /etc/init.d/charon-agentd-ssp restart).

 Remember that the automatically assigned public IP address changes when the instance is restarted (this is different from a persistent Elastic IP addresses).