The Kubernetes Dashboard is disabled by default on GKE versions 1.10 and higher.
You can disable the Kubernetes Dashboard add-on to conserve cluster resources. There is little or no downside to disabling the dashboard because it is redundant to the GKE dashboards available in Google Cloud Platform Console.
To disable the dashboard:
gcloud container clusters update [CLUSTER_NAME]
--update-addons=KubernetesDashboard=DISABLED
To enable to dashboard:
gcloud container clusters update [CLUSTER_NAME]
--update-addons=KubernetesDashboard=ENABLED