Exercises G21

Description:
The app allows browsing and reading articles even when not logged in,but when I tried to write a comment,it prompted me to log in.After providing my credentials and clicking on the Log In button the app crashed abruptly.
Steps to reproduce:

1. Launch the app on a mobile device.
2. Browse through the app without logging in and read articles.
3. Attempt to write a comment on an article,triggering the login prompt.
4. Enter valid credentials in the provided fields.
5. Click on the Log In button.
6. The app crashes immediately,exiting to the device's home screen.
7. Restart the app.
8. Repeat steps 2-5 to log in again.
9. Notice that the app crashes consistently upon clicking the Log In button.
   Expected Result:
   After entering valid login credentials and clicking on the Log In button, the app should successfully authenticate the user and allow access to the comment section or redirect to the desired page.
   Actual Result:
   Upon clicking the Log In button, the app crashes abruptly, preventing successful authentication and access to additional features.