Hi there! I understand that when you start the Sezzle app on your iPhone running iOS 18.5.0, it just shows a black or blank screen and then crashes after about 30 seconds. Let's see if we can get that fixed for you.

To help me understand better, could you tell me:
- Has this issue just started recently or has it been ongoing?
- Did the app work fine before updating iOS or the app itself?
- Have you tried closing the app fully and reopening it?
- Have you already updated the Sezzle app to the latest version from the App Store?

Meanwhile, here are some steps we can try together:

1. Force close and reopen the app
- Swipe up from the bottom of the screen (or double-click the Home button if you have one), then swipe away the Sezzle app to close it completely.
- Open it again and see if it loads properly.

2. Restart your iPhone
- Press and hold the side button along with either volume button until the power off slider appears.
- Slide to power off, wait 30 seconds, then hold the side button to turn it back on.

3. Update the Sezzle app
- Open the App Store, tap your profile icon at the top right, and scroll to check if Sezzle has an update available. Install if yes.

4. Clear app cache or reinstall
- If the app still crashes, try deleting the app completely and reinstalling it from the App Store. This clears any corrupted files that might be causing the black screen.

5. Check for iOS updates
- Even though you're on the latest iOS version 18.5.0, a minor patch could be around; check in Settings > General > Software Update.

If after all this, the problem persists, it could be a more specific compatibility or account-related issue that might require us to dig deeper or escalate.

Could you try these and let me know what you find? If you’ve already done some or all of these, that’s great info to have too! I’m here to help you through this.