Firebase connectivity issue in android studio

Question

I have used firebase for login purpose and it is working fine but when I am using firebase firestore database to retrieve already stored information it is showing failure and not able to retrieve(connect) to firebase database.
https://code.sololearn.com/clkpj9cfxPU9/?ref=app

Answer 1

Talha Iqbal please have a look at this.

Answer 2

Taste please have a look at this.