Thanks for sharing. This looks like there’s something happening with your instance on a server level, and an incorrect response is reaching the client, sending html instead of JSON.
Can you give us more details about how your instance is set up?
it seems that the backend is sending a 404 error with json response whille “fetching the info”. The frontend is parsing this json file during this initial setup.
But in our case the response with 404 status are caught by the proxy and a user friendly message in html is sent. So we need to configure our proxy (F5).
I suggest you configure the proxy to never catch and modify CHT responses, otherwise you risk exposing yourself to all sorts of other surprises like this - which might be less obvious to debug.