When you press it, in the top box, find Valid OAuth Redirect URIs and enter the Redirection URI. It will be @username/slug -- but if you're unsure, you can add the following to App.tsx and copy it from your console:
When you press it, in the top box, find Valid OAuth Redirect URIs and enter the Redirection URI. It will be @username/slug -- but if you're unsure, you can add the following to App.tsx and copy it from your console: