I've got the dashboard itself running and I can sign in using any of the service account tokens that can be obtained as given here. However, when I create a user using a token as shown here (by running kubectl config set-credentials myuser --token=some_token), I can't use that token to sign in to the dashboard as the authentication is rejected.

I found this question, and accordingly modified the API Server manifest after putting the token in a file. It works when I use username and uid default, but when I change both to myuser, it still logs in to default even after an API Server restart.

Why doesn't this work?

Cluster provisioned with kubeadm v1.8.1 on Ubuntu 16.04