Laravel prooblem getting Auth user, manual login user

I'm trying to authenticate my and user via ajax using axios in my laravel and vuejs app. the authentication is working well and returning the auth user like this:

public function loginUser(Request $request){
    $credentials = $request->only('email', 'password');
    if (Auth::attempt($credentials)) {
        // Authentication passed...
        $user = Auth::user();
         Auth::loginUsingId($user->id, TRUE);
        if (Auth::check()) {
            // The user is logged in successfully...
             return response()->json(Auth::id());
        }else{
            return response()->json("cannot chech user loggin user");
        }
    }else{
        return response()->json("failled authentication");
    }
}

This code is returning me the log's user id very well. the problem is when I triying to retrieve the Auth user in other function, like this:

public function testAuth(Request $request){
        // return response()->json(Auth::user());
        if (Auth::check()) {
            // The user is logged in...
            return response()->json(Auth::user());
        }else{
            return response()->json("the user is not login");

        }
}

The result that Im getting is "the user is not login" thank for help.

via Chebli Mohamed