App preview not loading

If the browser app preview is not loading or just showing a spinner, there are a few things you can check.

1. Make sure your WordPress website has the Reactor Core plugin installed and activated. Go to Plugins->Add New->search for Reactor Core. Install and activate.

2. Your app page is configured incorrectly. For example, you are using an incorrect category or custom post type. Double-check your slugs, or remove them to test.

3. Visit yoursite.com/wp-json/posts. If you see anything except a bunch of text (JSON data), then there is an issue. Deactivate all plugins except Reactor Core one by one to see if a plugin conflict is the issue. 

It could also be a server configuration issue, or caching. You can contact your web host for help in this area, let them know the WP-API is not working properly.