title: [Firebase/Core][I-COR000020] Error posting to Clearcut: Error Domain=NSURLErrorDomain Code=-1009 "The Internet connection appears to be offline
body: <p>I'm using FireBase SDK as the backend for my app and I have enabled persistence as required. </p>
  
  <pre><code>[FIRDatabase database].persistenceEnabled = YES;
  </code></pre>
  
  <p>Offline mode was working well until recently when I started getting this error when using my app in offline mode. </p>
  
  <pre><code>2017-01-08 19:03:44.838 MyApp[1002] &lt;Error&gt; [Firebase/Core][I-COR000020] Error posting to Clearcut: Error Domain=NSURLErrorDomain Code=-1009 "The Internet connection appears to be offline." UserInfo={NSUnderlyingError=0x170056710 {Error Domain=kCFErrorDomainCFNetwork Code=-1009 "(null)" UserInfo={_kCFStreamErrorCodeKey=50, _kCFStreamErrorDomainKey=1}}, NSErrorFailingURLStringKey=https://play.googleapis.com/log, NSErrorFailingURLKey=https://play.googleapis.com/log, _kCFStreamErrorDomainKey=1, _kCFStreamErrorCodeKey=50, NSLocalizedDescription=The Internet connection appears to be offline.}, with Status Code: 0
  </code></pre>
  
  <p>This is easily reproducible. Just switch between airplane mode on the iPhone and you see this error.</p>
  
  <p>I'm using CocoaPods to consume FireBase and here is the list of frameworks along with their versions.  </p>
  
  <pre><code>-&gt; Using Firebase (3.11.0)
  
  -&gt; Using FirebaseAnalytics (3.6.0)
  
  -&gt; Using FirebaseAuth (3.1.0)
  
  -&gt; Using FirebaseCore (3.4.6)
  
  -&gt; Using FirebaseDatabase (3.1.1)
  
  -&gt; Using FirebaseInstanceID (1.0.8)
  </code></pre>