Hi there! I’m sorry to hear that you’re having trouble signing into the Royal Caribbean International app. I can definitely help you with that.

To start, could you please let me know if you’re seeing any specific error messages when you attempt to log in? Also, have you made sure that you’re using the correct email and password for your account? Sometimes it can be as simple as that!

Let’s try a few steps:

1. Double-check your credentials: Make sure you’re entering the correct email and password. Sometimes typos can happen.

2. Reset your password: If you're unsure about your password, it might be a good idea to reset it. You can do this on the Royal Caribbean website and then try logging in again with the new password. Many users have found this helpful when they encounter issues signing in 1.

3. App update: Make sure that the app is updated to the latest version available on the App Store. Outdated apps can sometimes cause login issues.

4. Clear cache and data: On your iPhone, you can try closing the app completely and then reopening it. If this doesn't work, you could also uninstall the app and reinstall it from the App Store.

Let me know how it goes or if you’re encountering any specific messages while doing this! Your frustrations are completely understandable, and I’m here to help.