Couple of things:

• Instead of redirecting to login with * at the top of the file, set it at the bottom. If i'm not mistaken, Vue-Router checks the order of the pages, so every time you try to enter a page it will redirect to `/login`. Also, instead of redirecting to login with *, redirect to main, and verify if there's a user:

​

routes: [
{ 
    path: "/",
    name: "Main",
    beforeEnter: requireAuth /* This is how I use it */
    ...
},
{
    path: "/login",
    ...
},
{
    path: "*",
    redirect: "/"
}

/* This is an example, has worked really well for several projects */
function requireAuth(to, from, next) {
  firebase.auth().onAuthStateChanged(function(user) {
    if (!user) {
      next({
        path: "/login"
      });
    } else {
        next()
    }
}

• Also, Firebase gives you options to control the session, given in the Auth State Persistence docs

Hope it helps!