NetworkMatch.DropConnection not executing callback

Hello,

I'm currently exploring Unity Networking API, and having some problems with it. I wanted to create a button for a player to leave the "match", so i'm calling:

 matchMaker.DropConnection(currentMatchInfo.networkId, currentMatchInfo.nodeId, 0, OnDropConnection);

and I get log message in console, so I guess the request is made.

 MatchMakingClient DropConnection :https://mm.unet.unity3d.com/json/reply/DropConnectionRequest

Problem is that my OnDropConnection callback is never called, nor any error/warning/info appears in the log. Also tried with implementing OnDropConnection in my NetworkManager class, but neither is that called.

 public override void OnDropConnection(bool success, string extendedInfo)
 {
     base.OnDropConnection(success, extendedInfo);
     Debug.Log("OnDropConnection");
 }

Documentation doesn't state how to handle this.