Django: I have to login to admin site before the application
This might happen due to the following combination of circumstances:

The view you are accessing requires authentication (check for the @login_required decorator on the view)
Therefore, when you access anonymously it is trying to redirect you to the login page (check your LOGIN_REDIRECT_URL setting in settings.py)
Then, when your browser tries to reach this login page, it is not found (404)

So remove @login_required if it isn't really necessary, or make sure your login redirect is well configured and pointing to a url that actually provides a login page.
I have a weird problem with my Django application and I have no idea where to look to fix it. Whenever I run my application, before I can login to the application and do stuff on it I have to login to the admin site or else it throws a "Page not found (404)" error when I try to login to the application as a normal (non-admin) user.
Any ideas on what may be causing this and how I can fix it?