Failed to get FirebaseDatabase instance

[prathibhatvm]

java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.videocallapp/com.example.videocallapp.CallActivity}: com.google.firebase.database.DatabaseException: Failed to get FirebaseDatabase instance: Specify DatabaseURL within FirebaseApp or from your getInstance() call.

[prathibhatvm]

Issue resolved by adding FirebaseDatabase.getInstance() in onCreate method of MainActivity.kt