title: Mobile Center UITest exit code 20
body: <p>I've been trying to run a UI test via Visual Studio Mobile center for a while now, but I'm getting the following error:</p>
  
  <blockquote>
    <p>Preparing tests... failed.
    Error: Cannot prepare UI Test artifacts. Returning exit code 20.</p>
  </blockquote>
  
  <p>I looked on the mobile-center-cli github page and found that error codes 1 until 63 are reserved for TestCloud. There is really no documentation about this error so I hope someone is able to point me into the right direction.</p>
  
  <p>Command used:</p>
  
  <pre><code>mobile-center test run uitest --app "MyAppName" --devices d5c95903 --app-path "pathToApk"  --test-series "master" --locale "en_US" --build-dir "PathToBinRelease"
  </code></pre>