Hi there! I understand you're encountering a black and white screen when trying to log in to the Ambetter Health app on your iPhone running iOS 18.7. Let's work together to get this resolved.

To begin, can you clarify a bit more about the issue?
- Is the screen completely black and white (no colors at all), or is it just freezing on a login screen?
- Does this happen every time you try to log in, or intermittently?
- Have you recently updated the app or your iOS version?

Meanwhile, here are some steps we can try to fix this login screen issue:

1. Force Close and Restart the App
- Swipe up from the bottom of your iPhone screen and pause in the middle (or double-click Home button if your iPhone has one) to open the app switcher.
- Find the Ambetter Health app and swipe it up to close.
- Reopen the app to see if the screen displays properly.

2. Check for App Updates
- Open the App Store, tap your profile icon at the top right, then scroll to check if Ambetter Health has an update available.
- Updating the app can often resolve display bugs like the one you describe.

3. Restart Your iPhone
- Sometimes a simple restart can clear any minor glitches. Hold down the side button and either volume button, then slide to power off. Wait a few seconds, then power it back on.

4. Delete and Reinstall the Ambetter App
- Press and hold the app icon, tap "Remove App", then "Delete App".
- Go to the App Store and reinstall Ambetter Health. This can fix issues caused by corrupted app data.

5. Check Device Settings for Accessibility or Display
- Go to Settings > Accessibility > Display & Text Size and ensure that no unusual filters or settings are enabled that could cause a black and white effect.

6. Test Connectivity
- Make sure your iPhone is connected to a stable internet connection (Wi-Fi or cellular). Sometimes loading issues can cause blank or white screens.

If after trying these, the problem persists, it's worth checking if there's any scheduled maintenance or server issues affecting the Ambetter app recently. There have been reports that earlier this year some users faced login screen issues that were fixed in app updates1 2.

Lastly, if none of these work, I can guide you on contacting Ambetter support directly for further assistance or escalate the issue.

Could you please try these steps and let me know what happens? Are you satisfied with the solution I provided so far?