Hi there! I see you're having trouble logging into the QuikTrip app on your iPhone running iOS 18.5. To help you out better, could you tell me if the login fails with an error message or does the app just not respond? Also, have you tried any steps already to fix it? That way, I can avoid repeating those.

In the meantime, here’s a straightforward way to troubleshoot login issues on your device:

1. Check Your Internet Connection: Make sure your iPhone is connected to a strong Wi-Fi or cellular network.
2. Force Close and Reopen the App: Swipe up from the bottom, find the QuikTrip app, and swipe it away to close fully. Then reopen it.
3. Update the App: Head to the App Store and check for any updates to ensure you have the latest version.
4. Restart Your iPhone: Sometimes a quick reboot clears up any temporary glitches.
5. Reset Password: If there’s an error about authentication, try using the 'Forgot Password' link to reset your login credentials.
6. Check for Any Authentication Methods: Some users need to verify login via DUO or an authenticator app, so ensure you have those configured if required.
7. Clear Cache (if possible): While iOS apps don’t have a direct cache clearing, uninstalling and reinstalling the app can help.

Let me know which of these you’ve tried or if there’s a specific error message popping up. From there, I can guide you further with deeper troubleshooting!