I have an AGOL connection message when starting my Experiment (see connect_agol.png).
If I click on OK, an error window opens with the message "client_id not specified" (see client_id.png).
If I click on "Cancel", the login window closes, and the Experience works correctly.
I think the problem is sharing a feature service.
The Experience feature service is a view of another feature service.
The view is shared in public.
If I share the original service in public, I no longer have the login window.
I checked the dataSources settings in the "config.json" file.
It is indeed the view which is configured.
My Experience is here: