App will work only for Admin user having Role Administrator. This App will work only after enable this module in your Drupal website. Also provide Base Url of your Drupal website without forward slash(/) at the end of your base url.
https://www.drupal.org/project/drupal_admin_app
you can test the App with below Demo URL and credentials
Base URL- https://www.digitalnadeem.com/d10
username - appuser
password - appuser