title: How to fix TNS Doctor Errors
body: <p>I'm trying to develop an app on mobile but I got some troubles when I run the command : </p>
  
  <pre class="lang-sh prettyprint-override"><code>$ tns doctor
  ✖ WARNING: adb from the Android SDK is not installed or is not configured properly.  
   For Android-related operations, the NativeScript CLI will use a built-in version of adb.
  To avoid possible issues with the native Android emulator, Genymotion or connected
  Android devices, verify that you have installed the latest Android SDK and
  its dependencies as described in http://developer.android.com/sdk/index.html#Requirements 
  
  ✖ WARNING: The Android SDK is not installed or is not configured properly. 
   You will not be able to run your apps in the native emulator. To be able to run apps
  in the native Android emulator, verify that you have installed the 
  latest Android SDK 
  and its dependencies as described in 
  http://developer.android.com/sdk/index.html#Requirements 
  
  ✖ Cannot find a compatible Android SDK for compilation. To be able to build for Android, install Android SDK 28 or later. 
   Run `$ sdkmanager` to manage your Android SDK versions. 
  
  ✖ You need to have the Android SDK Build-tools installed on your system. You can install any version in the following range: '&gt;=23 &lt;=28'. 
   Run `$ sdkmanager` from your command-line to install required `Android Build Tools`. In case you already have them installed, make sure 
  `ANDROID_HOME` environment variable is set correctly. 
  
  You have nativescript-cloud extension installed, so you can execute cloud builds, but your environment is not configured properly and you will not be able to execute local builds. To continue, choose one of the following options: 
  Select "Sync to Playground" to enjoy NativeScript without any local setup. All you need is a couple of companion apps installed on your devices.
  Select "Configure for Local Builds" to run the setup script and automatically configure your environment for local builds.
  Select "Skip Step and Configure Manually" to disregard this option and install any required components manually.
  ? To continue, choose one of the following options:  (Use arrow keys)
   Sync to Playground 
    Try Cloud Operation 
    Configure for Local Builds 
    Skip Step and Configure Manually
  </code></pre>