title: FBSession must be specified
body: <p>While trying to use FacebookSDK in an iOS app, I get this message:</p>
  
  <blockquote>
    <p>FBSDKLog: Error for request to endpoint ‘123654789?fields=name,supports_attribution,supports_implicit_sdk_logging,gdpv4_nux_enabled,gdpv4_nux_content':
    An open FBSession must be specified for calls to this endpoint</p>
  </blockquote>
  
  <p>Why exactly do I get this?</p>
  
  <p>I took the code from <code>HelloFacebookSample</code> provided with the FacebookSDK and put it into my app, but I must have missed some critical part.</p>