You must have statically configured ethernet interface to setup dhcp server.
Reconfigure ethernet interfaces...
General settings
Select IP version:
Enable DHCP server
Interface:
(maximum possible address range)
Starting IP address:
Ending IP address:
Address expiration time:
Information provided for clients
DNS server:
Search domain:
Default gateway:
Static addresses
IP address
MAC address
Computer name
New static address:
IP address:
MAC address:
Computer name:
Current dynamically allocated addresses
Computer name
MAC address
IP address
Expiration time