title: Connecting to janus server always hangs with hangup message from janus
body: <p>I have problem connecting to janus <code>janus.plugin.videoroom</code> plugin from iOS device using swift.
  Although every steps take place correctly but janus server send following message:</p>
  
  <pre><code>{
     "janus": "hangup",
     "session_id": 3201104494179497,
     "sender": 7759980289270843,
     "reason": "ICE failed"
  }
  </code></pre>
  
  <p>and disconnect.</p>
  
  <p>Debugging the messages of connecting to janus leads me to following:</p>
  
  <p>1- RTCIceGatheringState never changes to Completed</p>
  
  <p>2- The generated candidates are like following:</p>
  
  <pre><code>candidate:3215141415 1 udp 1686052607 w.x.y.z 57168 typ srflx raddr w.x.y.z rport 57168 generation 0 ufrag 340a network-id 1 network-cost 10
  </code></pre>
  
  <p>as you can see video and audio words are replaced by 1 and 0 respectively in the generated candidate.</p>
  
  <p>Do you have any idea about these two observations!</p>
  
  <p>And why janus send the <code>"ICE failed"</code> message?</p>