Hi! I understand that you're experiencing an issue with the SWISH app invitations on your iPhone running iOS 18.0, where you can only open the second invite and it closes immediately, and this is happening for the first time. Let's see if we can get this working smoothly for you.

To start, could you clarify a bit more for me? When you say you can open the second invite but it closes—do you mean it closes right after opening with no chance to interact? And with the first invite, is it not opening at all or behaving differently? Also, is this happening with invitations sent through SWISH app notifications, emails, or another way?

Meanwhile, here are some initial steps we can try:

1. Force close and restart the SWISH app: Sometimes the app needs a fresh start.
- Swipe up from the bottom of the screen and pause (or double-click the Home button if you have one), find the SWISH app preview, and swipe it up to close it.
- Then reopen the app and try opening those invites again.

2. Check for app updates:
- Open the App Store, tap your profile icon at the top right, then scroll to see if there’s an update available for SWISH. If yes, update it.

3. Restart your iPhone:
- Hold the side button and either volume button until the power off slider appears. Power off and then power on again.

4. Review notification permissions:
- Go to Settings > SWISH and make sure notifications are enabled.
- Sometimes an app needing read permissions on calendars or contacts may affect invite handling, so double-check permissions there too.

5. Clear cache if possible:
- SWISH app sometimes stores data that can get corrupted. If the app has an option in its settings to clear cache or refresh data, try that.

If you’ve already done any of these, please let me know which ones. If none of these help, we can explore more detailed options like reinstalling the app or checking your account settings.

Can you try these and tell me what happens? That way, I can guide you better.