title: SSLHandshakeException on Marshmallow
body: <p><strong>Situation</strong><br>
  I have built a small android app (sdk 21+) which connects to a server, fetches some data and displays it. For the connection i use the <code>OkHttp</code> library. Running in Android 7+ it all works just fine.<br>
  Also should mention that i am new to networking and do not have the biggest knowledge yet.</p>
  
  <p><strong>Problem</strong><br>
  Running on Android 6 (in my case api 23) i get the following exception.</p>
  
  <pre><code>java.security.cert.CertificateException:
  java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.
  </code></pre>
  
  <p>In my <code>network_security_config.xml</code> i have 3 <code>certificates</code> registered as my <code>trust-anchors</code><br>
  I can't make much of this exception and when searching for it on the internet i couldn't find anything helpful either.</p>
  
  <p><strong>Question</strong><br>
  What could case this problem and how could i fix it? Please try to keep it simple so i can understand it.</p>