Prior installations of Sentinel may include the IP. address as 127.0.0.2 in the /etc/hosts file if you had chosen Assign hostname to loopback address option during installation. This may cause communication issues with other servers or components. You must edit the file and remove this IP address.
To remove the IP address:
Open the /etc/hosts file.
Comment the entry for IP address 127.0.0.2.
Save the file.