Error from server (ServiceUnavailable): the server is currently unable to handle the request (get nodes.metrics.k8s.io)

[tonglv]

kube-api config
--requestheader-client-ca-file=/etc/kubernetes/ssl/ca.pem
--requestheader-allowed-names=aggregator
--requestheader-extra-headers-prefix=X-Remote-Extra-
--requestheader-group-headers=X-Remote-Group
--requestheader-username-headers=X-Remote-User \

kubectl top nodes

Error from server (ServiceUnavailable): the server is currently unable to handle the request (get nodes.metrics.k8s.io)

kubectl logs -f pod/metrics-server-7cccb5464-n8wwn -n kube-system -c metrics-server

I0404 05:21:09.136867 1 serving.go:273] Generated self-signed cert (apiserver.local.config/certificates/apiserver.crt, apiserver.local.config/certificates/apiserver.key)
[restful] 2019/04/04 05:21:10 log.go:33: [restful/swagger] listing is available at https://:443/swaggerapi
[restful] 2019/04/04 05:21:10 log.go:33: [restful/swagger] https://:443/swaggerui/ is mapped to folder /swagger-ui/
I0404 05:21:10.729295 1 serve.go:96] Serving securely on [::]:443
E0404 06:51:15.246723 1 reflector.go:322] github.com/kubernetes-incubator/metrics-server/vendor/k8s.io/client-go/informers/factory.go:130: Failed to watch *v1.Pod: Get https://10.254.0.1:443/api/v1/pods?resourceVersion=17196317&timeoutSeconds=434&watch=true: dial tcp 10.254.0.1:443: connect: connection refused

help me，thanks!