This only happens on Mac OS since docker engine works differently on Mac OS and can't reach docker IPs directly. One can edit docker-compose file and redirect keycloak on localhost same as unifiedpush server and comment out hack.sh entry point command. You should get auth UI but still it'll return 400 unauth for some reason. I think there is a bug that kc has to be initialized from localhost (docker IP in this case) before use can use it through masked address i.e IP of host machine. Anyway, still a major bug preventing docker/k8s deployments.