If you're experiencing an issue in the Teuida app where clicking "yes" to use a key to access a new lesson results in no action, follow these steps to troubleshoot and potentially resolve the problem:

1. Check for App Updates: Ensure that you have the latest version of the Teuida app installed. Go to the App Store, search for Teuida, and see if there is an update available. Install it if needed.

2. Restart the App: Close and reopen the Teuida app. Sometimes, restarting the application can resolve temporary glitches.

3. Reboot Your Device: If restarting the app doesn’t have any effect, try rebooting your iPhone. This clears temporary files and caches that might be causing issues.

4. Check Your Internet Connection: Make sure you have a stable internet connection. If you're using mobile data, switch to Wi-Fi if possible, or vice versa. A weak connection can disrupt functionalities.

5. Review Key Availability: Ensure you have valid keys available to use. Sometimes, there are limitations on how many keys can be accessed daily. If you encounter a message indicating that the keys have been used up, you may need to wait until the next refresh or get more keys through in-app options.

6. Try Another Lesson: Select a different lesson or feature within the app. This can help determine if the issue is specific to that particular lesson or a broader app issue.

7. Check App Permissions: Ensure that the Teuida app has the necessary permissions to function correctly, such as microphone access if needed. Go to your iPhone’s Settings > Privacy > Microphone, and ensure Teuida is enabled.

8. Uninstall and Reinstall the App: If the problem persists, consider uninstalling the app and then reinstalling it from the App Store. This can help if there are corrupted files in the previous installation.

9. Contact Support: If none of the above steps resolve the issue, it may be helpful to reach out to Teuida's customer support for further assistance. They may have additional insights or solutions.

10. Explore Online Communities: Check out discussions on platforms like Reddit or TikTok where users might share similar experiences and solutions about the app functioning - learn more - learn more.

By systematically working through these steps, you should be able to identify and hopefully resolve the issue with the Teuida app.