I created a cluster using the GCP playground here and tried to connect to that via terminal using the command below:
gcloud container clusters get-credentials cluster-1 --zone europe-west2-b --project playground-s-11-xxxxxxxx
then it asked me to first log in using
gcloud auth login. And when I tried to log in using the username and password provided in the GCP playground I get the error: 502 Bad Gateway.