After connecting my Gitlab repo to my self-putup Kubernetes cluster via Operations > Kubernetes, I want to install Helm Tiller via the GUI; but I get:

Something went wrong while installing Helm Tiller

Kubernetes error: configmaps "values-content-configuration-helm" already exists

There are no pods running on the cluster and kubectl version returns:

Client Version: version.Info{Major:"1", Minor:"11", GitVersion:"v1.11.2", GitCommit:"bb9ffb1654d4a729bb4cec18ff088eacc153c239", GitTreeState:"clean", BuildDate:"2018-08-07T23:17:28Z", GoVersion:"go1.10.3", Compiler:"gc", Platform:"linux/amd64"}

Server Version: version.Info{Major:"1", Minor:"11", GitVersion:"v1.11.2", GitCommit:"bb9ffb1654d4a729bb4cec18ff088eacc153c239", GitTreeState:"clean", BuildDate:"2018-08-07T23:08:19Z", GoVersion:"go1.10.3", Compiler:"gc", Platform:"linux/amd64"}

update

the output of kubectl get cm --all-namespaces:

NAMESPACE           NAME                              DATA AGE
gitlab-managed-apps values-content-configuration-helm 3    7d
...

deleting this namespace solves the issue!