iframe of Grafana is not working. Read a few threads about allowing anonymous logins. But cant alter the config setting (in hassio) without errors.
iframe of Grafana works on local network but not www.
However. If you click on the Grafana tab on the main navigation (on the left), then click back to a page with your iframes, it works.
The solution is probably dead simple but a google search is pretty full of (recent) requests for solution, with little definitive answers.