Firebase database doesnt work after publishing app to play store

Question

I have a problem. I've coded app in android studio. After publishing app to play store, firebase database doesn't work at all. I added SHA1 key to firebase console project settings, what can be wrong?

Any help appreciated.

I took SHA1 key from here:

Answer 1

I found solution, it's very weird though. The variables in class where i stored all the data enter image description here were not private. After i add private modifier to all variables problem was solved enter image description here