Lab 3.5 I cannot access the nginx web page from outside

Hello,
I have followed all the labs up to chapter 3 but I cannot complete Lab 3.5: the web page is not accessible from outside.
From my desktop I get this:

$ curl http://35.234.68.127:31412
curl: (56) Recv failure: Connection reset by peer

Of course, something similar happens with firefox.
31412 comes from kubectl get svc:

student@cp:~$ kubectl get svc
NAME         TYPE           CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP      10.96.0.1       <none>        443/TCP        4d21h
nginx        LoadBalancer   10.109.20.101   <pending>     80:31412/TCP   21m
 

The external IP I got from ifconfig.io:

student@cp:~$ curl ifconfig.io
35.234.68.127

In the introduction of Lab 3.5 it is written:

You can access a Service from outside the cluster using a DNS add-on or environment variables. We will use environment variables to gain access to a Pod.

But I have not seen any step in the exercise to do that. Or it was not clear to me that I was doing it...

Any idea how to fix this?
TIA

PS in this post I have replaced my actual IP to avoid problems.