Passing response from social provider back to API endpoint

I am trying to add social authentication to a laravel 5.8 API application using socialite. Following the documentation here https://laravel.com/docs/5.8/socialite#routing I created a SocialAuthController that wiill redirect the user to the provider auth page and handle the callback like this

...

use Socialite;

...

public function redirectToProvider($provider)
{
    return Socialite::driver($provider)->redirect();
}

public function handleProviderCallback($provider)
{
    // retrieve social user info
    $socialUser = Socialite::driver($provider)->stateless()->user();

    // check if social user provider record is stored
    $userSocialAccount = SocialAccount::where('provider_id', $socialUser->id)->where('provider_name', $provider)->first();

    if ($userSocialAccount) {

        // retrieve the user from users store
        $user = User::find($userSocialAccount->user_id);

        // assign access token to user
        $token = $user->createToken('string')->accessToken;

        // return access token & user data
        return response()->json([
            'token' => $token,
            'user'  => (new UserResource($user))
        ]);
    } else {

        // store the new user record
        $user = User::create([...]);

        // store user social provider info
        if ($user) {

            SocialAccount::create([...]);
        }

        // assign passport token to user
        $token = $user->createToken('string')->accessToken;
        $newUser = new UserResource($user);
        $responseMessage = 'Successfully Registered.';
        $responseStatus = 201;

        // return response
        return response()->json([
            'responseMessage' => $responseMessage,
            'responseStatus'  => $responseStatus,
            'token'           => $token,
            'user'            => $newUser
        ]);
    }
}

Added the routes to web.php

Route::get('/auth/{provider}', 'SocialAuthController@redirectToProvider');

Route::get('/auth/{provider}/callback', 'SocialAuthController@handleProviderCallback');

Then I set the GOOGLE_CALLBACK_URL=http://localhost:8000/api/v1/user in my env file.

When a user is successfully authenticated using email/password, they will be redirected to a dashboard that will consume the endpoint http://localhost:8000/api/v1/user. So in the google app, I set the URI that users will be redirected to after they are successfully authenticated to the same endpoint http://localhost:8000/api/v1/user

Now when a user tries to login with google, the app throws a 401 unauthenticated error.

// 20190803205528
// http://localhost:8000/api/v1/user?state=lCZ52RKuBQJX8EGhz1kiMWTUzB5yx4IZY2dYmHyJ&code=4/lgFLWpfJsUC51a9yQRh6mKjQhcM7eMoYbINluA58mYjs5NUm-yLLQARTDtfBn4fXgQx9MvOIlclrCeARG0NC7L8&scope=email+profile+openid+https://www.googleapis.com/auth/userinfo.profile+https://www.googleapis.com/auth/userinfo.email&authuser=0&session_state=359516252b9d6dadaae740d0d704580aa1940f1d..10ea&prompt=none

{
  "responseMessage": "Unauthenticated",
  "responseStatus": 401
}

If I change the URI where google authenticated users should be redirect to like this GOOGLE_CALLBACK_URL=http://localhost:8000/auth/google/callback the social user information is returned.

So how should I be doing it. I have been on this for a couple of days now.