Thanks for the information regarding Dashboard Loading.
I am trying to create a new dashboard and here I am chosing index pattern metrics-* which has no fields to select from.
Normally it should not be empty, right?
I guess that I have to delete metrics-* index pattern and load it again with metricbeat setup command as recommended here Error in index or visualisations for "[Metricbeat System] Overview ECS" - Elastic Stack / Beats - Discuss the Elastic Stack?
Thanks in advance