问Firebase数据库未存储数据，logcat未显示错误

EN

{
"rules": {
".read": true,
".write": true
}
}

package com.revorg.tictactoe

import android.content.Intent
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.Toast
import com.google.firebase.auth.FirebaseAuth
import com.google.firebase.auth.FirebaseUser
import com.google.firebase.database.FirebaseDatabase
import kotlinx.android.synthetic.main.activity_login.*

class Login : AppCompatActivity() {

var mFirebaseAuth: FirebaseAuth?=null

var database = FirebaseDatabase.getInstance()
var myRef=database.reference

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_login)

    mFirebaseAuth= FirebaseAuth.getInstance()
}

fun buLoginEvent(view:View){

    LoginToFirebase(etEmail.text.toString(),etPassword.text.toString())
}

fun LoginToFirebase(email:String,password:String){

    mFirebaseAuth!!.createUserWithEmailAndPassword(email,password)
            .addOnCompleteListener(this) {task ->

                if(task.isSuccessful){
                    Toast.makeText(applicationContext,"Login Successful",Toast.LENGTH_SHORT).show()
                    var currentuser = mFirebaseAuth!!.currentUser
                    //save to Database
                    if(currentuser!=null) {
                        myRef.child("Users").child(splitString(currentuser.email.toString())).child(currentuser.uid)
                    }

                    LoadMain()

                } else {
                    Toast.makeText(applicationContext,"Login Failed", Toast.LENGTH_SHORT).show()
                }
            }

}

override fun onStart() {
    super.onStart()

    LoadMain()
}

fun LoadMain(){

    var currentuser = mFirebaseAuth!!.currentUser

    if(currentuser!=null) {


        var intent = Intent(this, MainActivity::class.java)
        intent.putExtra("email", currentuser.email)
        intent.putExtra("uid", currentuser.uid)

        startActivity(intent)
    }
}

fun splitString(str:String):String{

    var split = str.split("@")
    return split[0]
}
}