DHCP client not getting IPv4 address from a DHCP server

Question

I configured a DHCP server on a VM in VirtualBox. This machine has 2 network adapters, enp0s3 - NAT (from where I have my network connection) and enp0s8 - Internal Network (intnet). DHCP server is listening on enp0s8 interface.

Configurations:

    /etc/dhcp/dhcpd.conf   

option domain-name "sth.com";
option domain-name-servers ns1.sth.com, ns2.sth.com;
default-lease-time 600;
max-lease-time 7200;
authoritative;
log-facility local7;

subnet 10.0.3.0 netmask 255.255.255.0 {
range 10.0.3.20 10.0.3.30;
option domain-name-servers ns1.internal.sth.com;
option domain-name "internal.sth.com";
option routers 10.0.3.9;
option broadcast-address 10.0.3.255;
default-lease-time 600;
max-lease-time 7200;
}

/etc/sysconfig/dhcpd
DHCPDARGS=enp0s8

/etc/sysconfig/network-scripts/ifcfg-enp0s8
TYPE=Ethernet
BOOTPRO=static
NETWORK=10.0.3.0
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
NAME=enp0s8
DEVICE=enp0s8
ONBOOT=yes
BOOTPROTO=none
IPADDR=10.0.3.9
PREFIX=24
IPV6INIT=no

Atfer that, I started DHCP server:

      Active: active (running) since Wed 2016-04-27 15:00:50 EEST; 16min ago
     Docs: man:dhcpd(8)
           man:dhcpd.conf(5)
 Main PID: 863 (dhcpd)
   Status: "Dispatching packets..."
   CGroup: /system.slice/dhcpd.service
           └─863 /usr/sbin/dhcpd -f -cf /etc/dhcp/dhcpd.conf -user dhcpd -group dhcpd --no-pid

Apr 27 15:00:50 localhost.localdomain dhcpd[863]: Sending on   LPF/enp0s8/08:00:27:e6:ef:ca/10.0.3.0/24
Apr 27 15:00:50 localhost.localdomain dhcpd[863]: 
Apr 27 15:00:50 localhost.localdomain dhcpd[863]: No subnet declaration for enp0s3 (10.0.2.15).
Apr 27 15:00:50 localhost.localdomain dhcpd[863]: ** Ignoring requests on enp0s3.  If this is not what
Apr 27 15:00:50 localhost.localdomain dhcpd[863]:    you want, please write a subnet declaration
Apr 27 15:00:50 localhost.localdomain dhcpd[863]:    in your dhcpd.conf file for the network segment
Apr 27 15:00:50 localhost.localdomain dhcpd[863]:    to which interface enp0s3 is attached. **
Apr 27 15:00:50 localhost.localdomain dhcpd[863]: 
Apr 27 15:00:50 localhost.localdomain dhcpd[863]: Sending on   Socket/fallback/fallback-net
Apr 27 15:00:50 localhost.localdomain systemd[1]: Started DHCPv4 Server Daemon.

I installed another VM that will be a DHCP client. In the /etc/sysconfig/network-scripts/ifcfg-enp0s8 file, I wrote this lines:

DEVICE=enp0s8
BOOTPRO=dhcp
NAME=enp0s8
ONBOOT=yes

After that, I restarted network on client machine: systemctl restart network But, the client machine is not getting an IP for enp0s8 interface, from that range that I specified in dhcpd.conf .

Can someone explain me, what I am doing wrong there???