Firebase authentication for database write permission

i am creating a nes app in which i am only i will be able to change the news.
I am using firebase realtime database so that anyone can see the news my current firebase database rules loo like this:
Screenshot (40)

this means i am only allowing an authenticated owner that is myself to write the data and anyone to read the data.

Then i also enabled email authentication method in firebase and created a user with my email and a new password

then i am using firebaseAuth extension in mit app inventor to sign myself in the firebase whenever i want to change the news

and this is how my current authentication blocks look like.
Screenshot (44)_LI

It is of course opening the vertical arrangement in which i can edit the news but when i am making changes to news and saving changes database is not updating and the app is crashing
I request you to help if you know the solution to my problem!!

You might have a good read here:

and here

For Security Rules see here: