title: Parse.User.currentAsync() returns null
body: <p>I have an expo app. I'm using AsyncStorage from react-native.</p>
  
  <p>The app is set up with Parse as follows:</p>
  
  <pre><code>import Parse from 'parse';
  import { AsyncStorage } from 'react-native';
  
  Parse.initialize("r...", "2...");
  Parse.serverURL = 'https://parseapi.back4app.com/';
  Parse.setAsyncStorage(AsyncStorage);
  </code></pre>
  
  <p>I can log in log out, etc fine. </p>
  
  <p>But when I'm using 
  Parse.User.currentAsync() after successful login, I get null as a response. This means I cannot re-use previous sessions and have to log in every time the app is launched.</p>
  
  <p>I've added <code>Parse.User.enableUnsafeCurrentUser();</code> just before calling currentAsync() and login() as well, but makes no difference. I'm stuck.</p>
  
  <p>Any idea why this is happening?</p>
  
  <p>Many thanks</p>