Fb.Feed dialog closes before saving

I'm having trouble with the Facebook UnitySDK when I use the FB.Feed() method for posting on user's timeline. The share dialog closes before the post is completed, Right after i press the "Post" button. This only happens when I test the app on the iOS Device since on the Unity Editor it works fine and I can post on the user's wall. User Login and getting username and profile pic, for example, work fine. The problem is when I try to share the user's score on facebook. Here's my code for the method:

public void Share_Score(){
        FB.Feed (
            toId: "",
            link: "http://www.facebook.com/appname",
            linkName: "App Name",
            linkCaption: "I just scored " + " points",
            linkDescription: "Playing this game is awesome!",
            actionLink:"http://www.facebook.com/appname",
            actionName: "Appname Fan Page" 
                );
    }

The only error that appears on XCode is the following: 2015-02-11 10:13:07.025 hotdogcontest[749:224865] FBSDKLog: FBLinkShareParams: only "http" or "https" schemes are supported for link thumbnails