pop a ViewController animated

I'm trying to pop a view controller which includes Unity3D animation.

Any clue why this code does not work ?

 AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
 [appDelegate.navigationController popViewControllerAnimated:YES];

Update:

The hierarchy of my app looks like:

 AppDelegate
 -HomeViewController
 --VC1
 ---VC11 - this is the Unity View Controller (from here I want to top to VC1)