How can I troubleshoot the 'auth/configuration-not-found' error in my React app?

First, double-check that you've imported the Firebase SDK correctly. Then, ensure `firebase.initializeApp()` is called *before* any Firebase Authentication methods are used. Verify that your Firebase project ID is correct in the initialization call. Also, check for any typos or errors in your import statements or initialization code. Finally, ensure your Firebase configuration object is accessible in the scope where you're using it.