Некоторая ошибка в моем тестовом проекте с retrofit2 с gson

Question

У меня есть некоторые проблемы с retrofit2 в моем первом тестовом проекте Android Kotlin.и мое приложение показывает сообщение об ошибке - Конец ввода в строке 1, столбец 1, путь $

Кто-нибудь сталкивался с этой проблемой?

Я добавил это разрешение

<uses-permission android:name="android.permission.INTERNET"/>

Build Gradle

implementation 'com.squareup.retrofit2:retrofit:2.4.0'
implementation 'com.squareup.retrofit2:converter-gson:2.4.0'
implementation 'com.squareup.okhttp3:logging-interceptor:3.10.0'

Журнал HTTP

D/OkHttp: --> POST http://192.168.1.106/login.php
D/OkHttp: Content-Type: application/x-www-form-urlencoded
D/OkHttp: Content-Length: 29
D/OkHttp: login=admin&password=ADr00tAD
D/OkHttp: --> END POST (29-byte body)
D/OkHttp: <-- 200 OK http://192.168.1.106/login.php (48ms
D/OkHttp: Server: nginx/1.14.2
D/OkHttp: Date: Thu, 02 May 2019 10:13:39 GMT
D/OkHttp: Content-Type: text/html; charset=UTF-8
D/OkHttp: Transfer-Encoding: chunked
D/OkHttp: Connection: keep-alive
D/OkHttp: <-- END HTTP (0-byte body)
D/Error:::: End of input at line 1 column 1 path $

проверить мой сервер API отдыха https://i.ibb.co/cTFsQ8J/Screenshot-from-2019-05-02-16-14-33.png

<- Интерфейс IMyAPI ->

package com.example.root.myapplication.Remote
import com.example.root.myapplication.Model.APIResponse
import retrofit2.Call
import retrofit2.http.Field
import retrofit2.http.FormUrlEncoded
import retrofit2.http.POST
interface IMyAPI {
    @FormUrlEncoded
    @POST("login.php")
    fun loginUser(@Field("login") login: String, @Field("password") password: String):Call<APIResponse>
}

<- Класс APIResponse ->

package com.example.root.myapplication.Model
import com.google.gson.annotations.Expose
import com.google.gson.annotations.SerializedName
class APIResponse {

    @SerializedName("error")
    @Expose
    var error: Boolean=false

    @SerializedName("err_msg")
    @Expose
    var err_msg:String?=null

    var User:User?=null
}

<- Пользователь класса ->

package com.example.root.myapplication.Model

import com.google.gson.annotations.Expose
import com.google.gson.annotations.SerializedName

class User {

    @SerializedName("name")
    @Expose
    var name: String = ""

    @SerializedName("email")
    @Expose
    var email: String = ""

    @SerializedName("role")
    @Expose
    var role: String = ""
}

<- Объект RetrofitClass ->

package com.example.root.myapplication.Remote

import retrofit2.Retrofit
import retrofit2.converter.gson.GsonConverterFactory
import okhttp3.OkHttpClient
import okhttp3.logging.HttpLoggingInterceptor

object RetrofitClass{
    private var retrofit:Retrofit?=null
    fun getClient(baseUrl:String):Retrofit{
        if (retrofit == null)
        {
            val interceptor = HttpLoggingInterceptor()
            interceptor.level = HttpLoggingInterceptor.Level.BODY
            val client = OkHttpClient.Builder()
                    .addInterceptor(interceptor)
                    .build()

            retrofit = Retrofit.Builder()
                    .baseUrl(baseUrl)
                    .addConverterFactory(GsonConverterFactory.create())
                    .client(client)
                    .build()

        }
        return retrofit!!
    }
}

<- Object Common ->

package com.example.root.myapplication.Common
import com.example.root.myapplication.Remote.IMyAPI
import com.example.root.myapplication.Remote.RetrofitClass

object Common {
    val BASE_URL = "http://192.168.1.106/" //I'm using my phone
    val api: IMyAPI
        get() = RetrofitClass.getClient(BASE_URL)!!.create(IMyAPI::class.java)
}

<- MainActivity ->

package com.example.root.myapplication
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.util.Log
import android.widget.Toast
import com.example.root.myapplication.Common.Common
import com.example.root.myapplication.Model.APIResponse
import com.example.root.myapplication.Remote.IMyAPI
import kotlinx.android.synthetic.main.activity_main.*
import retrofit2.Call
import retrofit2.Callback
import retrofit2.Response

class MainActivity : AppCompatActivity() {

    internal var mServise:IMyAPI? = null

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

        mServise = Common.api
        println(mServise)
        btn_login.setOnClickListener{authenticateUser(edt_login.text.toString(),edt_password.text.toString())}
    }

    private fun authenticateUser(login: String, password: String) {

        mServise!!.loginUser(login,password)
                  .enqueue(object :Callback<APIResponse>{
                    override fun onFailure(call: Call<APIResponse>?, t: Throwable?) {
                        //Toast.makeText(this@MainActivity, response!!.body,Toast.LENGTH_LONG).show()
                        Toast.makeText(this@MainActivity, t!!.message,Toast.LENGTH_SHORT).show()

                        Log.d("Error:::",t?.message)
                    }

                    override fun onResponse(call: Call<APIResponse>?, response: Response<APIResponse>?) {

                        if (response!!.body()!!.error)
                            Toast.makeText(this@MainActivity,response!!.body()!!.err_msg,Toast.LENGTH_SHORT).show()
                        else
                            Toast.makeText(this@MainActivity,"Login Success!!!",Toast.LENGTH_SHORT).show()
                    }

                })
    }
}