Android studio can not resolve EstimoteSDK

I followed all the steps of EstimateDSK android;
Create libs directory inside your project and copy there estimote-sdk.aar.
In your build.gradle add flatDir entry to your repositories

repositories {
flatDir {
dirs ‘libs’
Add dependency to Estimote SDK. All needed permissions (BLUETOOTH, BLUETOOTH_ADMIN and INTERNET) and services will be merged from SDK’s AndroidManifest.xml to your application’s AndroidManifest.xml.

dependencies {
compile(name:‘estimote-sdk’, ext:‘aar’)
Initialize Estimote SDK in your Application class onCreate() method - if you are using Estimote Cloud:

// App ID & App Token can be taken from App section of Estimote Cloud.
EstimoteSDK.initialize(applicationContext, appId, appToken);
// Optional, debug logging.

how can i resolve this problem :\

Why not use Gradle via Maven Central installation option?

It’s easier, no need to worry about putting the .aar file in the right directory, etc.