isAuthenticated() is always false

Hey, I’m new to Auth0.
I managed to make the react and javascript sample work but now I need to make it work for ExtJs.

The login seems to work but the isAuthenticated returns always false.
The app is going in a loop : isAuthenticated = false → Login → already logged → IsAuthenticated = false → …

Probably a code issue as the application settings in auth0 works for the sample apps.

Edit : auth0.user is undefined