1. how to execute /scripts/configure_firewall_for_cpanel
2. not able to access the http://139.162.201.216:2086

2015-07-16 14:02:47 738 ( INFO): Congratulations! Your installation of cPanel & WHM 11.50 is now complete. The next step is to configure your server.
2015-07-16 14:02:47 738 ( INFO):
2015-07-16 14:02:47 738 ( INFO): Before you configure your server, ensure that your firewall allows access on port 2087.
2015-07-16 14:02:47 738 ( INFO): On RHEL, CentOS, and CloudLinux systems, execute /scripts/configure_firewall_for_cpanel to accomplish this

You'll need to get into a shell via SSH or LISH and execute that command

/scripts/configure_firewall_for_cpanel

This may fix the firewalling issue you're having.

i getting this error

The system cannot get the firewall's default-zone. Is the 'firewalld.service' running?

even not able to access http://139.162.201.216:2086/ or https://139.162.201.216:2087/

Assuming you are on CentOS 7, systemctl status firewalld.service will answer that question. If it is not installed, then yum install firewalld will install it.

For example,

$ systemctl status firewalld.service
firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled)
   Active: active (running) since Mon 2015-07-13 00:13:21 EDT; 4 days ago
 Main PID: 2671 (firewalld)
   CGroup: /system.slice/firewalld.service
           `-2671 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid

$ yum info firewalld
Installed Packages
Name        : firewalld
Arch        : noarch
Version     : 0.3.9
Release     : 11.el7
Size        : 2.3 M
Repo        : installed
From repo   : base
Summary     : A firewall daemon with D-BUS interface providing a dynamic
            : firewall
URL         : http://fedorahosted.org/firewalld
License     : GPLv2+
Description : firewalld is a firewall service daemon that provides a dynamic
            : customizable firewall with a D-BUS interface.

its worked for 1 hour now stopped https://139.162.201.216:2087/cpsess4040 ... ?gswdone=1