Login bug fix for a React Native app

We need a developer to fix a login issue in an existing React Native app. The work includes identifying the root cause, resolving the problem, and testing the fix to ensure the login flow works reliably. You should be comfortable reviewing existing code, debugging mobile app issues, and making targeted changes without breaking other parts of the app. Please share relevant experience with React Native mobile app fixes and your approach to troubleshooting login-related problems.