Hi! Thanks for reaching out. I see you're encountering two issues with the United Airlines app: an error saying "not working, try again" and another that says your email is invalid. To help you better, could you tell me:

1. When you see the "not working, try again" message—does it happen at app launch, during login, or when performing a specific action?
2. Regarding the email error, are you entering the email to log in, sign up, or reset the password?
3. Have you already tried any troubleshooting steps like restarting the app, checking your internet connection, or updating the app?

Once I have this info, I can guide you step-by-step toward fixing this. Meanwhile, here's a general approach we can start with:

1. Check your email input: Make sure the email you type has no extra spaces and follows the usual format: [email protected]. Typos or missing characters often trigger invalid email errors.

2. Update the United app: Outdated app versions can cause random errors. Please go to Microsoft Store on your Windows device to check for updates and install the latest version.

3. Restart your device: A quick reboot often clears temporary glitches.

4. Verify internet connection: Ensure your connection is stable. Try switching from Wi-Fi to Ethernet or vice versa if possible.

5. Clear app cache/data: Though this is more typical on mobile, on Windows you can try reinstalling the app to clear corrupted data causing failures.

If after these steps the email problem persists, it could be related to backend validation or service issues, which may require more advanced troubleshooting or contacting support directly.

Let me know what you've tried or any extra details you have, and we’ll get this resolved together! Are you able to provide that info?