Celebrate a victory with Open Graph on iOS - ios

Question

After almost 2 days of reading through the Facebook docs, I still can't figure out why oh why my code for simply publishing a game victory does not work. If I use Facebook Sample's object, it does work (uncommented), but once I use the object, the app crashes and opens the browser (in simulator) and returns to the game again. The code is as follows:
NSDictionary *properties = #{
#"og:type": #"games.victory",
#"og:title": #"A Game Victory",
#"og:description": #"Awsum description",
};
FBSDKShareOpenGraphObject *object = [FBSDKShareOpenGraphObject objectWithProperties:properties];
// Create an action
FBSDKShareOpenGraphAction *action = [[FBSDKShareOpenGraphAction alloc] init];
action.actionType = #"games.celebrate";
[action setString:#"http://samples.ogp.me/500426766634310" forKey:#"victory"];
// [action setObject:object forKey:#"victory"];
// Create the content
FBSDKShareOpenGraphContent *content = [[FBSDKShareOpenGraphContent alloc] init];
content.action = action;
content.previewPropertyName = #"victory";
[FBSDKShareDialog showFromViewController:self
withContent:content
delegate:nil];
What am I doing wrong and how can I fix this, I'm quite done with the FB documentation. Also, how could I know whether the story has been posted successfully in my app? Is there some delegate callback function or anything like that?