I don't have permission to log in using GitHub

[tangshuya]

1. cd js-powergate-client/examples/node
2. npm install
3. I have generated a new OAuth app in GitHub developer settings and take note of the generated client id and secret.
4. I update GITHUB_CLIENT_ID and GITHUB_CLIENT_SECRET with the values from the above step
5. npm run build
6. npm start
7. Finally, navigate to http://localhost:3000 and I see the app being running locally!
8. Click the button with "Login with GitHub" text，But It shows that I don't have permission
   Look at the picture below.