Firewalla NextDNS Cli help

I posted this on the Firewalla reddit group, but no success so far, so hoping someone can help here.

I'm trying to run NextDNS via Cli rather than HTTPS so I can see individual device names within the NextDNS logs.

This is the guide I followed -> https://github.com/nextdns/nextdns/wiki/Firewalla

The picture is the message I get. 

Can anyone help point me in the right direction please? I've reached out to NextDNS, but we all know how responsive they can be, so I'm hoping someone knowledgeable on here can help.