What happens if you open the metrics URL?

By default the metrics certificate is self signed and not trusted by the browser. So you will first need to click on the link and verify if you trust the certificate or not. If you accept the certificate and refresh the metrics page, do you still see the error?

If not, you might be running into an issue. If that is the case, can you please attach the output of 'oc get pods -n openshift-infra' to see what state each of the pods are in?