That's just an outgoing connection to some HTTPS webserver, not your webserver listening on port 80.
You might be able to get a certificate with the --standalone plugin, but then you'd need to install that certificate manually into whatever webserver Nextcloud uses.. And you won't be able to easily renew it, as ultimately there's gonna be a webserver running and that would interfere with the --standalone authenticator, unless stopped before renewing..
If the --standalone authenticator doesn't work, there's either a problem with the IP address (is 83.83.165.172 the correct IP address of the host?) or some routing issue (NAT portmap, Docker mapping or some strange iptables mapping from port 80 to something else..).
the plan for now is to reset the network when everyone is asleep and try one more time since local also does not work. like even without https it does not want to work