RedHat 7 snmpd service failed due to Name or service not known

I have a RedHat 7 server installed, but I cannot start the snmpd service due to:

server11# systemctl status snmpd
 snmpd.service - Simple Network Management Protocol (SNMP) Daemon.
 Loaded: loaded (/usr/lib/systemd/system/snmpd.service; enabled; vendor preset: disabled)
 Active: failed (Result: exit-code) since Tue 2017-12-12 11:51:13 CET; 25min ago
 Process: 20736 ExecStart=/usr/sbin/snmpd $OPTIONS -f (code=exited, status=1/FAILURE)
 Main PID: 20736 (code=exited, status=1/FAILURE)

Dec 12 11:51:13 oitwi11 systemd[1]: Starting Simple Network Management Protocol (SNMP) Daemon....
Dec 12 11:51:13 oitwi11 snmpd[20736]: getaddrinfo: serverz1-oam Name or service not known
Dec 12 11:51:13 oitwi11 snmpd[20736]: getaddrinfo("serverz1-oam", NULL, ...): Name or service not known
Dec 12 11:51:13 oitwi11 snmpd[20736]: Error opening specified endpoint "serverz1-oam:161"
Dec 12 11:51:13 oitwi11 snmpd[20736]: Server Exiting with code 1

Well, the error is clear, snmpd service cannot find the serverz1-oam hostname. So, solution could be add it to hosts file. But this is not correct because the real hostname is "server11". I checked the /etc/snmp/snmpd.conf, but there isn't such config to change. So, how can I instruct snmp to getaddress to server11 hostname?

Many thanks Lucas