Currently if there is an http error while loading the web app there is a big chance that a JS error will be raised, resulting in an infinite spinner displayed to the user. The user should either be redirect (for 401 status) or have an error message.
Here is an exemple of how to reproduce the bug :
- in admin settings, Security section, switch on 'Force user authentication'
- analyse one project, copy-paste the URL of the project homepage
- try to navigate to the URL you copy-pasted -> infinite loading spinner
- hitting refresh at this point does display the login form afterwards