Child View not scrolled inside the ContainerView - Objective C

Question

Container View is fixed with Bottom half of the screen, On Button click current container view will replace with the new View Controller. Each sub view have a different size in height. Sub view Scroll is not working. I checked with many answers but solutions found. The code is

    UIStoryboard *storyBoard = [UIStoryboard storyboardWithName:@"Main" bundle:[NSBundle mainBundle]];
    UIViewController *viewController = nil;
    viewController = [storyBoard instantiateViewControllerWithIdentifier:@"First"];
    // lets add it to container view
    [viewController willMoveToParentViewController:self];
    [self.containerViewController addSubview:viewController.view];
    [self addChildViewController:viewController];
    [viewController didMoveToParentViewController:self];