Hi there! I’m sorry to hear that your onX Hunt app won’t open on your iPhone. To help you best, could you tell me if you see any error message when you try to open the app, or does it just stay stuck or close immediately? Also, have you tried any troubleshooting steps already?

Meanwhile, here’s a good starting point to get things working again on your iOS 18.6 device:

1. Restart your iPhone. Simply turn it off and back on. This often clears up minor glitches.

2. Check for app updates.
- Open the App Store.
- Tap your profile icon at the top right.
- Scroll down to see if onX Hunt has an update waiting. If yes, tap Update.

3. Force-close and reopen the app.
- On iPhone models with a Home button, double tap it; on yours, swipe up from the bottom and pause.
- Swipe up on the onX Hunt app card to close it, then tap the icon to relaunch.

4. Check your network connection. The app sometimes needs internet to open initially. Try switching from Wi-Fi to cellular data or vice versa, then open the app.

5. Reinstall the app. If none of the above work:
- Press and hold the onX Hunt app icon, tap Remove App > Delete App.
- Go back to the App Store and download it fresh.

6. If you use any VPN, security software, or have limited permissions/settings, temporarily disable or adjust those as they might block the app.

Let me know if you've tried any of these or if something specific happens when you open the app. We can definitely dig deeper based on what you tell me!