Error 401 when accessing public dashboard from iPhone

I have very recently created a public dashboard on Grafana Cloud that works generally fine from laptop browsers, but does pop an “Unauthorized” message each time when starting it on an iPhone. However, it does work on the iPhone despite that error message.
I managed to see the message briefly when using google chrome on a laptop and could trace it to a GET for https://…/api/plugins/grafana-pdc-app/settings.
I tried various AUTH settings in the Grafana Cloud console, but did not really make any impact on that message. If anyone has a suggestion on how to proceed, I would be very grateful.
PS: Looking through existing posts, there are some similar problems but all of them ended up with changing settings in the home assistant. In my case, it is a plain iPhone Safari browser that has no corresponding configuration options.