AngularFire 2 authState returning null on Page Refresh

I am using firebase with AngularFire 2.

My issue is that when I a try to refresh the page, the auth instance is returning null.

This is code for my auth Service.

Everything works fine, but whenever I refresh the page, the auth is null and I am unable to call firebase database as my rules required user to be authenticated.

export class AuthService {
private userDetails: Users = null;
private dbUsers;
public loginStatus = new BehaviorSubject(false);

public GOOGLE_OATH_SCOPES = 'email, https://www.googleapis.com/auth/drive';

constructor(
    private _firebaseAuth: AngularFireAuth,
    private router: Router,
    private firebase: AngularFireDatabase,
    private _userService: UserService
) {
    var currentUser = JSON.parse(localStorage.getItem('currentUser'));
    this.setUserFromLocalstorage(currentUser);
    _firebaseAuth.authState.subscribe(
        (user) => {
             console.log("Step 1",user);
            if (user) {

            }
            else {
                this.setUserFromLocalstorage(currentUser);
            }
        }
    );

}
setUserFromLocalstorage(currentUser) {
    if (currentUser && !_.isEmpty(currentUser)) {
        this.userDetails = currentUser;
    } else {
        this.userDetails = null;
    };
}
signInWithGoogle() {
    var provider = new firebase.auth.GoogleAuthProvider();
    provider.setCustomParameters({
        prompt: 'select_account'
    });
    provider.addScope(this.GOOGLE_OATH_SCOPES);
    this._firebaseAuth.auth.setPersistence(firebase.auth.Auth.Persistence.NONE).then(() =>
        this._firebaseAuth.auth.signInWithPopup(
            provider
        ).then((result) => {
            localStorage.setItem('accessToken', result.credential.accessToken);
        })
    )
}

isLoggedIn() {
    if (!this.loginStatus.value) {
        return false;
    } else {
        return true;
    }
}


logout() {
    this._firebaseAuth.auth.signOut()
        .then((res) => {
            this.router.navigate(['/'])
            localStorage.clear()
            this.userDetails = null;
            this.loginStatus.next(false);
        }
        );

}


getLoggedInUser() {
    return _.cloneDeep(this.userDetails);
}

setLoggedInUser(user: Users) {
    this.userDetails = user;
    localStorage.setItem("currentUser", JSON.stringify(user));
}

}

And AngularFireAuth :

export declare class AngularFireAuth {
    private zone;
    readonly auth: FirebaseAuth;
    readonly authState: Observable<User | null>;
    readonly idToken: Observable<string | null>;
    constructor(config: FirebaseOptions, name: string, platformId: Object, zone: NgZone);
}

My SignIn Method :

this._firebaseAuth.auth.setPersistence(firebase.auth.Auth.Persistence.None).then(() =>
                this._firebaseAuth.auth.signInWithPopup(
                    provider
                ).then((result) => {

                })
    )

How can I resolve this issue?