You open the app.
The login screen loads normally.
You enter your email and password.
You tap the login button.
The screen disappears instantly.
The app closes without warning.
This is one of the most frustrating app failures.
Everything looks fine until the exact moment authentication begins.
In this case, the app is not failing at launch.
It is failing when it tries to process login data.
When you tap the login button, the app sends credentials to a server.
It also initializes session data, security checks, and account validation.
If any part of that chain breaks, the app shuts down immediately.
No error message appears.
No loading screen is shown.
This often happens when stored login data is corrupted.
It can also occur after an update that changes authentication rules.
From the user’s perspective, the app feels unstable.
In reality, the crash is tightly linked to the login action itself.
If the app only closes when you press the login button,
the issue is not the app interface.
It’s the authentication process failing in real time.