If you're trying to log in to 1SE using your Apple ID but are getting an error message, here's how to fix it:
- Open the Settings app, then tap [your name].
- Tap Password & Security.
- Tap Apps Using Your Apple ID.
- Select 1 Second Everyday: Video Diary from the list.
- Tap Stop Using Apple ID at the bottom of the screen.
- Tap Stop Using in the alert shown.
- Open 1SE, then open the Profile tab.
- Tap the Sign In or Create Account button.
- Select Continue with Apple and follow the sign-in process.
For additional information, here's a helpful article by Apple on this feature: https://support.apple.com/en-us/HT210426.