OpenVPN Unrecognized option or missing or extra parameter

I have a .conf file which contains below information but openvpn says something is missing.

cat ./vpnconf.conf
client

gateway [IP]
ID GRDVPN
secret [SECRET]
username [USERNAME]
password [PASSWORD]
MTU 1380

sudo openvpn --config  ./vpnconf.conf 
Options error: Unrecognized option or missing or extra parameter(s) in ./VPN_access_to_VF_lab_-_keep_confidential/copy-conf.vpn:4: gateway (2.4.4)
Use --help for more information.

What I am doing wrong?

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Author: AVarf