Changing the constant property does not change the frame size and gives an error. IBOutlet in storyboard is correct. 
An error appears on the line with the assignment of a new constant; the initial value is 263.
self.heightConstraint.constant = 1115; [self.view layoutIfNeeded]; error text:
Unable to simultaneously satisfy constraints. Probably at least one of the constraints in the following list is one you don't want. Try this: (1) look at each constraint and try to figure out which you don't expect; (2) find the code that added the unwanted constraint or constraints and fix it. ( "<NSLayoutConstraint:0x147d7b00 V:[UIView:0x15fc41c0(1115)]>", "<NSLayoutConstraint:0x14771cb0 V:[UIView:0x147eba20]-(0)-[UIView:0x15fc41c0]>", "<NSLayoutConstraint:0x14709e10 V:[UIView:0x147eba20]-(263)-[UIView:0x15fa7b90]>", "<NSLayoutConstraint:0x146ba4b0 V:[UIView:0x15fc41c0]-(0)-[UIView:0x15fa7b90]>" ) Will attempt to recover by breaking constraint <NSLayoutConstraint:0x147d7b00 V:[UIView:0x15fc41c0(1115)]> What am I doing wrong ?