Hi there! I understand you're having trouble opening the Days After game on your iPhone with iOS 16.7.15. Let's work together to get this sorted out.

First, could you tell me a bit more? For example:
- When you try opening the game, does it crash, freeze, or just not respond at all?
- Have you recently updated the game or your iOS?
- Do you see any error messages?
- Have you tried restarting your iPhone or reinstalling the game yet?

Meanwhile, here’s a step-by-step approach that usually helps with apps that won’t open:

1. Restart Your iPhone: Press and hold the side button and either volume button until the slider appears. Slide to power off, wait about 30 seconds, then turn it back on. This often resolves temporary glitches.

2. Check for Updates:
- Open the App Store, tap your profile icon at the top right, then scroll down to see if Days After has an update available. If so, update it.

3. Reinstall the Game:
- Press and hold the Days After app icon until a menu appears.
- Tap "Remove App," then "Delete App" to uninstall it.
- Go back to the App Store, search for Days After, and reinstall the game.
- Note: If your game progress is saved on an account or cloud, make sure you're signed in to restore it.

4. Free Up Storage:
- Low storage can prevent games from running smoothly.
- Go to Settings > General > iPhone Storage to see if you have enough free space.

5. Check for iOS Updates:
- Although you're on 16.7.15, it’s good to confirm you have the latest updates in Settings > General > Software Update.

If you’ve tried these already or if the problem persists, let me know so I can guide you through some more advanced checks like looking at background apps, permissions, or potential account issues with Days After.

How does this sound? Do you want to start with the restart and update checks?