The error message was "ERROR: (gcloud.container.clusters.get-credentials) environment variable HOME or KUBECONFIG must be set to store credentials for kubectl"
After research in the internet I found the solution, I will describe how to fix the issue.
Set environment variable:
then execute the following in the (under current user) command line:
mkdir .kube
cd .kube
echo "" > config
because you make the config file under current user gcloud should have the right permissions:
Source: https://github.com/kubernetes/kubernetes/issues/34395