Hi there! I understand that your Waterllama app won’t open on your iPhone running iOS 17.5.1. Let's see if we can get it working for you.

To start, could you tell me if the app crashes immediately when you tap it, or does it just stay stuck on a loading screen? Also, have you tried any troubleshooting steps yet, like restarting your phone or reinstalling the app?

Meanwhile, here’s a simple step-by-step approach to try:

1. Force Close and Reopen the App
Double-press the Home button (or swipe up from the bottom if your iPhone doesn’t have a Home button) to bring up the app switcher. Find Waterllama, swipe it up to close it, then tap the app icon again.

2. Restart Your iPhone
Sometimes just restarting clears temporary glitches. Press and hold the side button with the volume up or down button until the power off slider appears. Slide to power off, then after a minute, press the side button to turn it back on.

3. Check for App Update
Open the App Store, tap your profile icon at the top right, then scroll to see if Waterllama has an update available. Installing an update might fix bugs.

4. Reinstall the App
If the above doesn’t help, press and hold the Waterllama app icon until it wiggles, tap the “X” or “Remove App,” then confirm deletion. After that, open the App Store and download Waterllama again.

5. Check for iOS Update
Go to Settings > General > Software Update to make sure you have the latest iOS 17.5.1 update installed, as sometimes app compatibility depends on this.

Once you try these, let me know how it went or if you get any error messages. We’ll take it from there! Are you able to try these steps now?