UIScrollView is not scrolling while the scroll view height is set to 1000 and the content height 2000

Question

I am building an application form for data entry in iPad app, that needs more space.I decided to use the UIScrollView for that purpose and added some subviews (UILabel, UITextField,...). The only problem I am facing is that scrolling is not working !!

Here is .h code :

 @interface ViewController4_modified : UIViewController<UIScrollViewDelegate>

 @property (weak,nonatomic) IBOutlet UIScrollView *formScroller; // <-- 
 @property (weak, nonatomic) IBOutlet UILabel *formLabel;
 @property (weak, nonatomic) IBOutlet UITextField *formFisrtNameTextField;
 @property (weak, nonatomic) IBOutlet UITextField *formFirstMidTextField;
 @property (weak, nonatomic) IBOutlet UITextField *formSecondMidTextField;
 @property (weak, nonatomic) IBOutlet UITextField *formLastNameTextField;
 @property (weak, nonatomic) IBOutlet UIPickerView *formGenderPicker;
 @property (weak, nonatomic) IBOutlet UIDatePicker *formBDDatePicker;

 @end

Here is .m code:

 - (void)viewDidLoad {    

self.formScroller.scrollEnabled = YES;
self.formScroller.contentSize = CGSizeMake(768, 2000);
self.formScroller.contentInset = UIEdgeInsetsMake(64.0, 0.0, 44.0, 0.0);
self.formScroller.scrollIndicatorInsets = UIEdgeInsetsMake(64.0, 0.0, 44.0, 0.0);


[super viewDidLoad];

// Do any additional setup after loading the view from its nib.

}