Not sure if this is how things just work, but why is the home page trying to load, then the sign-in page? I imported the DataTable module (from the app store), which is executing a MF to pull data (clearly shown on a line in the log). After the system redirects to the sign-in page, I get this: If I use any other page as the home page there is no error. I don’t think the system should be triggering MFs on a page that should not be loading in the first place. I’m using Mendix 8.3 (which is not even in the version list when posting by the way).
When an anonymous user is trying to see data which it is not allowed to see the user is redirected to the login screen. So that is the reason for the loading of the login screen. Double check the access rights of the page you are trying to load.