Cannot get OpenVPN to work on my RBK50 Wifi Router/Satellite system

Followed all videos and written instructions on how to set up the VPN on the Orbi router, but cannot connect to OpenVPN. Get the certificate validation error (WARNING: No server certificate verification method has been enabled. See http://openvpn.net/howto.html#mitm for more info.).

Tried adding the "remote-cert-tls server" line to the end of the config file, but it doesn't work either.

Any other non-programming, easy to implement solution ?

Thanks !