Android app crash. Small issue to fix. Need quick support

Hi, I have uploaded my app to the play store. But it is showing a crash issue. I think this can be solved in 10-15 min.
The crash is - "com.google.firebase.database.DatabaseException: "
If you are good at this work please contact me.
Sorry, my budget is 600 INR. But if you will do this work for me then I will give you more work for sure.

Please bid.