DHCP Relay Invalid type "dhcp" in listen section

Hi, i have problem when i configured for dhcp relay, i have configured ./sites-enabled/dhcp-relay according to https://github.com/FreeRADIUS/freeradius-server/blob/master/raddb/sites-avai... and i have included dictionary.dhcp in ./dictionary config file, but i still got error *Debug: listen {* *Debug: type = "dhcp"* *Error: /etc/raddb/sites-enabled/dhcp.relay[12]: Invalid type "dhcp" in listen section.* listen type dhcp is not recognize, can anybody help me? Thanks before